Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on August 10, 2012, 10:44:01 PM
Post by: Quietleaf on August 10, 2012, 10:44:01 PM
Here's a little tip for those of us without EATC: we all know that the connector to the fan switch is pr0ne to melting. Ford actually redesigned it a few years later to run the current through a relay when the fan is switched to Hi. A few years ago I rewired it using my 1997 Explorer EVTM as a guide, and hopefully the connector won't ever melt again. It's a pretty easy project for anyone who is interested.
Title: Protecting your blower motor switch (non-EATC)
Post by: Crazy88 on August 10, 2012, 11:29:46 PM
Post by: Crazy88 on August 10, 2012, 11:29:46 PM
Do you have details to share? This sounds like a worthwhile project to undertake, especially if you are already in the dash doing something like replacing a heater core or something else of that nature.
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 11, 2012, 12:11:43 AM
Post by: jcassity on August 11, 2012, 12:11:43 AM
yeah, ill put it up on my photo bucket link with your credits within the evtm bundle.
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on August 11, 2012, 12:14:03 AM
Post by: Quietleaf on August 11, 2012, 12:14:03 AM
Well, I don't have a scanner, but I do have a digital camera:
The diagram doesn't specify what kind of relay, but I used a 50A one just in case. Explorers use two sizes of relays, big square ones and ones that are half that size. This is the larger kind. They come in different amp ratings, so be careful which one you use. I also used a relay block from a 1995-ish Taurus for mounting the relay, but that might have been more trouble than it was worth since I had to replace all the wires with heavier-gauge ones. I went that route to avoid any chance of short-circuits between relay terminals. There are aftermarket mounting blocks for single relays which is what I would use if I had to do it again.
The diagram doesn't specify what kind of relay, but I used a 50A one just in case. Explorers use two sizes of relays, big square ones and ones that are half that size. This is the larger kind. They come in different amp ratings, so be careful which one you use. I also used a relay block from a 1995-ish Taurus for mounting the relay, but that might have been more trouble than it was worth since I had to replace all the wires with heavier-gauge ones. I went that route to avoid any chance of short-circuits between relay terminals. There are aftermarket mounting blocks for single relays which is what I would use if I had to do it again.
Title: Protecting your blower motor switch (non-EATC)
Post by: Crazy88 on August 11, 2012, 01:02:07 AM
Post by: Crazy88 on August 11, 2012, 01:02:07 AM
Awesome, Thank you!
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 12, 2012, 11:39:17 AM
Post by: jcassity on August 12, 2012, 11:39:17 AM
This should do fine, not sure if this is what you ended up with or not but i cant see over complicating it.
Notice the R&R of the original fuse to 5A (approx).
You can intercept the existing DB/LG wire for the relay then apply ground & power as shown.
Notice the R&R of the original fuse to 5A (approx).
You can intercept the existing DB/LG wire for the relay then apply ground & power as shown.
Title: Protecting your blower motor switch (non-EATC)
Post by: Crazy88 on August 12, 2012, 12:04:58 PM
Post by: Crazy88 on August 12, 2012, 12:04:58 PM
Thanks jcassity, that is terrific!
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 12, 2012, 12:19:24 PM
Post by: jcassity on August 12, 2012, 12:19:24 PM
let it cyclel through here a couple days, several eyes on things are better than one set.
Im now working on headlamp relays while jacking with this amp guage converting it by using a volt meter. digikey has a few.
Im now working on headlamp relays while jacking with this amp guage converting it by using a volt meter. digikey has a few.
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on August 12, 2012, 03:51:52 PM
Post by: Quietleaf on August 12, 2012, 03:51:52 PM
I don't see how that protects the blower motor switch...it protects the multifunction switch (which is a mod I hadn't considered), but it still routes all the current through the blower motor switch when set to Hi.
Apologies if I hadn't been clear about which switch I was protecting. It looks like we have two good mods here.
Apologies if I hadn't been clear about which switch I was protecting. It looks like we have two good mods here.
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 12, 2012, 04:02:46 PM
Post by: jcassity on August 12, 2012, 04:02:46 PM
ok, you missed calling out which one you were protecting. Will fix now.
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on August 12, 2012, 04:09:57 PM
Post by: Quietleaf on August 12, 2012, 04:09:57 PM
I think your mod is also valid, maybe they should be combined?
Title: Protecting your blower motor switch (non-EATC)
Post by: hwy73 on August 12, 2012, 05:50:45 PM
Post by: hwy73 on August 12, 2012, 05:50:45 PM
Quote from: Quietleaf;395817
I think your mod is also valid, maybe they should be combined?
Agreed. Jcassity's mod protects the function contol switch, which isn't a bad thing, as it is the hot side to the blower. Quietleaf wants to protect the blower speed switch, which we know melts the connector because that black-out "hi-speed" is carrying the full current load on the ground side, which would require that dual-relay gimmick to switch the ground, correct?
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 12, 2012, 06:22:00 PM
Post by: jcassity on August 12, 2012, 06:22:00 PM
i just about broke my head trying to figure this out without as you called it a dual slave of a slave relay.
I think i nailed it,,, circuit is de-energized now on paper.
Add power to the upstream relay and power is also applied to the lower downstream relay coil and common contact after the motor.
**when high speed is selected the lower relay coil gets an open ground but the power for the motor is now able to see ground from the contacts.
this just might fly,, any thoughts?
I think i nailed it,,, circuit is de-energized now on paper.
Add power to the upstream relay and power is also applied to the lower downstream relay coil and common contact after the motor.
**when high speed is selected the lower relay coil gets an open ground but the power for the motor is now able to see ground from the contacts.
this just might fly,, any thoughts?
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on August 12, 2012, 07:26:01 PM
Post by: Quietleaf on August 12, 2012, 07:26:01 PM
Hmm. That doesn't look quite right. I believe this is what I had to do:
Edit: scratch that. Mine isn't right either...
Edit: scratch that. Mine isn't right either...
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on August 12, 2012, 08:36:00 PM
Post by: Quietleaf on August 12, 2012, 08:36:00 PM
Got it. Now I remember: I had to put the relay after the Hi output:
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 12, 2012, 08:42:32 PM
Post by: jcassity on August 12, 2012, 08:42:32 PM
yea, your catching power upstream of the blower motor which is more electrically correct.
this was a little tricky to think through with a single relay, my hats off to you!!.... i sat here for 45min trying to figure out how to control that high speed ground lead then it hit me,,, "eye don need no stinkin grownd down theyr"
this was a little tricky to think through with a single relay, my hats off to you!!.... i sat here for 45min trying to figure out how to control that high speed ground lead then it hit me,,, "eye don need no stinkin grownd down theyr"
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 12, 2012, 08:45:13 PM
Post by: jcassity on August 12, 2012, 08:45:13 PM
LOL,, see, they did what i did, they are powering the relay downstream of the motor.
I like your first version, now why is your first version not a good choice?>
I like your first version, now why is your first version not a good choice?>
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 12, 2012, 08:52:48 PM
Post by: jcassity on August 12, 2012, 08:52:48 PM
looking at your revision, and granted there are several ways to do this,,, dont you think they went the long way around the track? i just traced it out and it makes a complete circle back into the coil which then the relay coil picks the very same ground the contacts are picking.
interesting but im dizzy
interesting but im dizzy
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 12, 2012, 08:57:04 PM
Post by: jcassity on August 12, 2012, 08:57:04 PM
I think my point is "what will work" is what the attempt is here..... not "what did you do" to get it to work.
Granted the layout above on post 15 works,,,
What is the benefit and how is it different from your deleted solution and the one i have posted?
Granted the layout above on post 15 works,,,
What is the benefit and how is it different from your deleted solution and the one i have posted?
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 12, 2012, 09:01:51 PM
Post by: jcassity on August 12, 2012, 09:01:51 PM
another interesting thing, once you select "HIGH", that allows the blower coil to energize but in effect the "HIGH" contact now becomes open as the relay has latched to the secondary path. They are also basically deleting the ground leg off pin1 of the switch but using it for the time it takes to prime the coil only.
Title: Protecting your blower motor switch (non-EATC)
Post by: Crazy88 on August 12, 2012, 09:24:03 PM
Post by: Crazy88 on August 12, 2012, 09:24:03 PM
Perhaps I am confused, but in one of these revisions, the secondary (bottom) relay in the closed position removes the needed ground from the blower motor completely, while in another, direct ground is applied to the fused (30A) source through the primary relay. quietleaf's last post however, appears to be exactly what is necessary to protect the blower switch in high from over current, but still relies on the thermal limiter for the low and medium positions, as originally designed. Exactly how much protection the switch really has with so little resistance can only be determined by actually measuring the current when the the blower is in operation at these two remaining levels.
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on August 12, 2012, 09:33:04 PM
Post by: Quietleaf on August 12, 2012, 09:33:04 PM
Here's my final one, cleaned up...
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on August 12, 2012, 09:38:54 PM
Post by: Quietleaf on August 12, 2012, 09:38:54 PM
Here's my final one, cleaned up...
Title: Protecting your blower motor switch (non-EATC)
Post by: Crazy88 on August 12, 2012, 09:50:04 PM
Post by: Crazy88 on August 12, 2012, 09:50:04 PM
Yes indeed, this revision will work fine. Do you have a ford part number for the "high speed relay" or will any Bosch compatible 30A relay work? Also, does anyone have a source for new connectors or connector pigtails and pins?
Title: Protecting your blower motor switch (non-EATC)
Post by: TOM Renzo on August 12, 2012, 09:52:08 PM
Post by: TOM Renzo on August 12, 2012, 09:52:08 PM
Slave relays are used to control high current applications. Most every switch in early fords suffered this dilemma. That is why so many of them found their way to the JUNK YARD as they burned to the ground. Over the years i have slaved out the headlights the fog lights the MFS. the blower motor and absolutely the IGNITION SWITCH. The stock wiring is heavy enough to handle the loads. But the switches are not as good and they get hot and melt. Not only the device the plug also. I have checked current flow through the ignition switch and it can exceed 50 AMPS. Basically just about all the heavy current draw switches have to be slaved. This is a pain to someone that lacks electrical knowledge. But never the less it has to be dun. Sooner or later the switches will melt. Slave relays can handle the loads quite well and are very common today on modern cars. learn how to wire them and you will be saving your ride from a possible melt down.
Fog light plug. Burnt pretty bad. I see so many of these .
(http://i740.photobucket.com/albums/xx46/proguns/001-48.jpg)
All connections must be crimpedand soldered for a good connection. Below is a low high beam relay mod!!
(http://i740.photobucket.com/albums/xx46/proguns/002-27.jpg)
Fog light plug. Burnt pretty bad. I see so many of these .
(http://i740.photobucket.com/albums/xx46/proguns/001-48.jpg)
All connections must be crimpedand soldered for a good connection. Below is a low high beam relay mod!!
(http://i740.photobucket.com/albums/xx46/proguns/002-27.jpg)
Title: Protecting your blower motor switch (non-EATC)
Post by: Crazy88 on August 12, 2012, 09:53:59 PM
Post by: Crazy88 on August 12, 2012, 09:53:59 PM
Great advice Tom, thank you.
Title: Protecting your blower motor switch (non-EATC)
Post by: TOM Renzo on August 12, 2012, 09:59:26 PM
Post by: TOM Renzo on August 12, 2012, 09:59:26 PM
88 try this
http://www.repairconnector.com/
http://www.repairconnector.com/
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 13, 2012, 08:12:37 AM
Post by: jcassity on August 13, 2012, 08:12:37 AM
hey tom,
pls comment on the blower slave relay for both my design and quietleaf's layout.
wanna get these over to eric for a coolcats adder when reviewed and approved.
pls comment on the blower slave relay for both my design and quietleaf's layout.
wanna get these over to eric for a coolcats adder when reviewed and approved.
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 13, 2012, 08:45:53 AM
Post by: jcassity on August 13, 2012, 08:45:53 AM
Quote from: Crazy88;395839
Perhaps I am confused, but in one of these revisions, the secondary (bottom) relay in the closed position removes the needed ground from the blower motor completely, while in another, direct ground is applied to the fused (30A) source through the primary relay. quietleaf's last post however, appears to be exactly what is necessary to protect the blower switch in high from over current, but still relies on the thermal limiter for the low and medium positions, as originally designed. Exactly how much protection the switch really has with so little resistance can only be determined by actually measuring the current when the the blower is in operation at these two remaining levels.
Ignore the top relay in both layouts, just pretent its not there and pass power directly to the blower motor.
-in my layout......
-power is applied to the coil of relay 2 and the postions of the contacts are switched.
-as you move the blower speed switch through the low, m2, & m1 positions, the blower motor gets its ground through the resistor bank.
-when you flip to "HI" however, the relay "de-energizes" and obtains its own ground as shown bypassing the blower switch.
-my design never uses the oem ground for "HI"
In quietleaf's layout, ignore the top relay and follow the same steps.
-his second relay stays "de-energized" during low, m1 & m2 but energizes during "HI"
-when "hi" is selected, power passes through the blower switch then comes around and energizes the coil
-the second relay contacts now are moved and the "HI" selection is now an open from pin 1 to pin 2.
~his uses the oem "HI" ground momentarily only as the alternate path is taken thus bypassing it.
a few thouths on my layout
- simpler to wire
-less retrofit wire required,
- you would have "HI" only if the relay coil were to fail and would be consistent with oem troubleshooting symptoms.
-my relay is energized during low, m1 & m2 and could increase current demand more often since its "on" three times longer.
a few toughts on his layout
-relay is de-energized duirng low, m1 & m2
-requires more retrofit wire
-tad bit more complicated to wire
-you would have low, m1 & m2 only if the relay coil were to fail
-you would use less power as the second relay is on only during the "HI" event.
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on August 13, 2012, 09:07:23 PM
Post by: Quietleaf on August 13, 2012, 09:07:23 PM
I must be missing something :( I still don't see how switching to Hi de-energizes the coil in your design. Circuit 261 will always draw some current.
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 14, 2012, 07:50:56 PM
Post by: jcassity on August 14, 2012, 07:50:56 PM
I looked over my layout and you are correct, man what an oversight on my part,, when hi is selected we get "LOW"
I looked back at your layout and bounced it off the explorer page you posted.
I believe you have a problem with your layout in that the relay should clatter all the time when high is selected.
When hi is switched on, its wire delivers power out to the coil of your relay and then the relay see's ground potential. At this point it switches the contacts poistions and thus removes power delivery to the coil,,,, this process should repeat itslef and you would hear a clatter.
See what i mean?
For the past couple days off and on i have not been able to nail a "bypass on HI" relay mod because that stinking ckt 261 keepts screwing me over.
IF "LOW" were ommitted from the layout (ckt 261) then my version would work. Low is nice to have but sometimes low is "too low" for my winter time tastes.
what say you ?
I looked back at your layout and bounced it off the explorer page you posted.
I believe you have a problem with your layout in that the relay should clatter all the time when high is selected.
When hi is switched on, its wire delivers power out to the coil of your relay and then the relay see's ground potential. At this point it switches the contacts poistions and thus removes power delivery to the coil,,,, this process should repeat itslef and you would hear a clatter.
See what i mean?
For the past couple days off and on i have not been able to nail a "bypass on HI" relay mod because that stinking ckt 261 keepts screwing me over.
IF "LOW" were ommitted from the layout (ckt 261) then my version would work. Low is nice to have but sometimes low is "too low" for my winter time tastes.
what say you ?
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on August 15, 2012, 10:39:21 PM
Post by: Quietleaf on August 15, 2012, 10:39:21 PM
Ugh. You're right. Would this solve the problem?
Edit: never mind. I don't think this would work either. The ground would still bypass the blower motor switch. Any upstream ground would. I need to think about this some more.
Edit: never mind. I don't think this would work either. The ground would still bypass the blower motor switch. Any upstream ground would. I need to think about this some more.
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on August 15, 2012, 11:15:45 PM
Post by: Quietleaf on August 15, 2012, 11:15:45 PM
Okay, maybe this one...it basically follows the Explorer method by reversing the current through the switch and the resistor pack. I think I've convinced myself that the only way this can work is to have the relay upstream of the Hi setting.
EDIT: Another light in my brain flickered on (albeit dimly). You also have to swap the pins on the connector to the blower resistor to get the fan speeds right. revised diagram below...
EDIT #2: Revised the terminal pinout diagram in the small box in the lower right.
EDIT #3: Minor cosmetic cleaning up (no circuit changes).
EDIT #4: Unswapped M1 and M2 pins on the resistor pack (good catch, Crazy88).
EDIT: Another light in my brain flickered on (albeit dimly). You also have to swap the pins on the connector to the blower resistor to get the fan speeds right. revised diagram below...
EDIT #2: Revised the terminal pinout diagram in the small box in the lower right.
EDIT #3: Minor cosmetic cleaning up (no circuit changes).
EDIT #4: Unswapped M1 and M2 pins on the resistor pack (good catch, Crazy88).
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 16, 2012, 12:55:42 AM
Post by: jcassity on August 16, 2012, 12:55:42 AM
Welp,,, you nailed it, hats off to you. I didnt know we were allowed to repin things,,,just kidding and its likely one solution.
I bet you put a lot of work into the above recent adjustment, my head just about split dealing with a solution.
However, i have a new idea that just hit me and it appears you and i are "over here" when we should be "over there"
what i mean is if we copy cat the explorer version, it actually (and successfully) manages heat / watts most correctly.
You may not have noticed but on the explorer laout, the rotary switch is down stream of the speed resistor bank.
In our drawing we've been muddling through, our speed switch is upstream of the resistor bank.
In effect, there is still a sensible heat gain in the switch on all speeds except high because you have managed to place this contact on the direct ground leg. GREAT WORK!
I paid really close attention to post 21 by Crazy88 because in his comments, and intent, he said exactly what we both know needs done.
I would suggest we position the speed switch downstream of the resistor bank and effectively using this switch to select the respective resistor bank tap off point and control the ground only.
when high is selected, the motor can gain its own ground on a separate bonding point as per the oem Explorer design.
I am regrouping now, but with my schedule, i bet you will beat me to it.
thanks for helping me with this, Im not perfect by no measure.
I bet you put a lot of work into the above recent adjustment, my head just about split dealing with a solution.
However, i have a new idea that just hit me and it appears you and i are "over here" when we should be "over there"
what i mean is if we copy cat the explorer version, it actually (and successfully) manages heat / watts most correctly.
You may not have noticed but on the explorer laout, the rotary switch is down stream of the speed resistor bank.
In our drawing we've been muddling through, our speed switch is upstream of the resistor bank.
In effect, there is still a sensible heat gain in the switch on all speeds except high because you have managed to place this contact on the direct ground leg. GREAT WORK!
I paid really close attention to post 21 by Crazy88 because in his comments, and intent, he said exactly what we both know needs done.
I would suggest we position the speed switch downstream of the resistor bank and effectively using this switch to select the respective resistor bank tap off point and control the ground only.
when high is selected, the motor can gain its own ground on a separate bonding point as per the oem Explorer design.
I am regrouping now, but with my schedule, i bet you will beat me to it.
thanks for helping me with this, Im not perfect by no measure.
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 16, 2012, 02:48:48 AM
Post by: jcassity on August 16, 2012, 02:48:48 AM
ok,,
i think this might be the one, wire as shown, swap two connections at the dash, this way you dont have to fiddle with the resistor bank connector.
Puts selector switch on a ground source potential only.
lets review...........everyone put eyes on it.
i think this might be the one, wire as shown, swap two connections at the dash, this way you dont have to fiddle with the resistor bank connector.
Puts selector switch on a ground source potential only.
lets review...........everyone put eyes on it.
Title: Protecting your blower motor switch (non-EATC)
Post by: Crazy88 on August 16, 2012, 03:59:15 AM
Post by: Crazy88 on August 16, 2012, 03:59:15 AM
Um, No. This revision has couple of problems and I have them listed in no particular order.
The only way to completely protect the blower switch, which would be overkill in my opinion, would be to use three relays, one each for M1, M2 and High, used to pass grounds appropriately to the resistor pack (M1/M2) and bypassing it completely as the current revision does. As Tom pointed out earlier, we sometimes tend to over complicate things unnecessarily.
The source voltage for the secondary relay(s) should be the switched side of the heater function selector relay.
The best solution, thus far, would seem to be Quietleaf's last revision, but would need pins 4 & 6 his blower switch diagram switched for the blower switch to operate as I believe he intends, e.g. the M1 position resulting in a lower blower speed (more resistance) than the M2 position (less resistance).
I should make it clear that the switch current doesn't care whether or not the switch is switching ground or source voltage. The current draw through the circuit and thus the switch is all that matters.
One final thought before I move on, is that with the heater function selector switch now only providing switched power to the heater function relay, is it really necessary or even desirable to fuse it with a 5 amp fuse? What is the current draw on that relay and does that same fuse provide power to another circuit on on this diagram?
- As diagramed, applying ground through the blower switch on both M1 and M2 positions, bypasses the thermal limiter and at least a portion of the resistor pack, which will increase current through the blower switch in both these positions.
- With the blower switch in the high position AND applying ground through the blower switch, the secondary relay will either never energize, due to some lower source voltage (as measured at the top of the resister pack/bottom of the blower motor) or if it does energize, it will constantly cycle (chatter) due to the loss of voltage, since its voltage source is the same as the ground being applied to the bottom of the blower motor.
- The new fuse (30A) inline with the resister pack is redundant as the circuit is already fused (30A) upstream of the blower motor and it's feed through the relay.
The only way to completely protect the blower switch, which would be overkill in my opinion, would be to use three relays, one each for M1, M2 and High, used to pass grounds appropriately to the resistor pack (M1/M2) and bypassing it completely as the current revision does. As Tom pointed out earlier, we sometimes tend to over complicate things unnecessarily.
The source voltage for the secondary relay(s) should be the switched side of the heater function selector relay.
The best solution, thus far, would seem to be Quietleaf's last revision, but would need pins 4 & 6 his blower switch diagram switched for the blower switch to operate as I believe he intends, e.g. the M1 position resulting in a lower blower speed (more resistance) than the M2 position (less resistance).
I should make it clear that the switch current doesn't care whether or not the switch is switching ground or source voltage. The current draw through the circuit and thus the switch is all that matters.
One final thought before I move on, is that with the heater function selector switch now only providing switched power to the heater function relay, is it really necessary or even desirable to fuse it with a 5 amp fuse? What is the current draw on that relay and does that same fuse provide power to another circuit on on this diagram?
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 16, 2012, 09:21:24 AM
Post by: jcassity on August 16, 2012, 09:21:24 AM
the 15A fuse is back as shown , good point.
I really dont know what to make of the rest of what you shared. Current takes the path of least resistance.
why dont you trace out power and show me were this is wrong.
It mirrors the explorer layout. Ford did the same job with 2 relays and so can we.
I really dont know what to make of the rest of what you shared. Current takes the path of least resistance.
why dont you trace out power and show me were this is wrong.
It mirrors the explorer layout. Ford did the same job with 2 relays and so can we.
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 16, 2012, 09:24:36 AM
Post by: jcassity on August 16, 2012, 09:24:36 AM
i am surprised you didnt notice "why" i put the inline fuse down stream of K2.
Title: Protecting your blower motor switch (non-EATC)
Post by: Crazy88 on August 16, 2012, 02:21:25 PM
Post by: Crazy88 on August 16, 2012, 02:21:25 PM
Quote from: jcassity;396100
the 15A fuse is back as shown , good point.
I really dont know what to make of the rest of what you shared. Current takes the path of least resistance.
why dont you trace out power and show me were this is wrong.
It mirrors the explorer layout. Ford did the same job with 2 relays and so can we.
I am well versed in both whole flow and electron flow theories. As an ET in the US Navy, I have repaired and replaced more fuses, switches, wiring and other circuitry than I care to remember. Therefore, my understanding goes well beyond that of the typical shadetree mechanic and certainly beyond "path of least resistance".
Apparently, you have made some changes to your diagram subsequent to my last post, so it would appear that you came to understand my main points.
Yes, I agree that Ford did an adequate job of protecting the switch in the Explorer with only two relays, which is why I said that total protection using three relays was overkill in this application.
Lastly, tracing source voltage in the top half of the diagram, your primary relay, which I will call K1 and the "Heater Function Selector Switch" are now being protected by a 15 amp fuse instead of a 5 amp fuse, which I will refer to as F1. I have no idea of why you went back to a 15A fuse in this circuit, unless this fuse also protects other circuits not shown on this diagram. However, as it is currently diagramed, and without anything to indicate otherwise, the 15 A fuse now only protects the "Heater Function Selector Switch and K1, which should as diagrammed only draw milliamps, just enough current to energize the relay K1. Therefore 15A is far too large a fuse for this circuit, as diagramed.
Source voltage on your secondary circuit, protected by a secondary fuse hereafter referred to as F2, flows through K1 and stops at the blower motor and the switched power side of your secondary relay, which I will call K2. If the blower motor shorts, it "could" cause damage to the blower switch before the F2 opens to protect the circuit.
Quote from: jcassity;396101
i am surprised you didnt notice "why" i put the inline fuse down stream of K2.
Maybe my eyes are not fully awake yet, but I failed to find a K2 label, but the moment, I'll make the assumption that it is your secondary relay. I still fail to see why the third fuse, which I will refer to as F3, is necessary or would open any faster than F2. Perhaps you can explain your reasoning and why even Ford didn't need the third fuse to protect the circuit.
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on August 16, 2012, 06:33:17 PM
Post by: Quietleaf on August 16, 2012, 06:33:17 PM
Good catch on my M1 and M2 pins. I unswapped them and revised my last diagram.
EDIT: never mind my comments about the fan speeds; they're the same... (smacks head).
EDIT: never mind my comments about the fan speeds; they're the same... (smacks head).
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 16, 2012, 11:44:35 PM
Post by: jcassity on August 16, 2012, 11:44:35 PM
Quote from: Crazy88;396113
I am well versed in both whole flow and electron flow theories. As an ET in the US Navy, I have repaired and replaced more fuses, switches, wiring and other circuitry than I care to remember. Therefore, my understanding goes well beyond that of the typical shadetree mechanic and certainly beyond "path of least resistance".
Apparently, you have made some changes to your diagram subsequent to my last post, so it would appear that you came to understand my main points.
Yes, I agree that Ford did an adequate job of protecting the switch in the Explorer with only two relays, which is why I said that total protection using three relays was overkill in this application.
Lastly, tracing source voltage in the top half of the diagram, your primary relay, which I will call K1 and the "Heater Function Selector Switch" are now being protected by a 15 amp fuse instead of a 5 amp fuse, which I will refer to as F1. I have no idea of why you went back to a 15A fuse in this circuit, unless this fuse also protects other circuits not shown on this diagram. However, as it is currently diagramed, and without anything to indicate otherwise, the 15 A fuse now only protects the "Heater Function Selector Switch and K1, which should as diagrammed only draw milliamps, just enough current to energize the relay K1. Therefore 15A is far too large a fuse for this circuit, as diagramed.
Source voltage on your secondary circuit, protected by a secondary fuse hereafter referred to as F2, flows through K1 and stops at the blower motor and the switched power side of your secondary relay, which I will call K2. If the blower motor shorts, it "could" cause damage to the blower switch before the F2 opens to protect the circuit.
Maybe my eyes are not fully awake yet, but I failed to find a K2 label, but the moment, I'll make the assumption that it is your secondary relay. I still fail to see why the third fuse, which I will refer to as F3, is necessary or would open any faster than F2. Perhaps you can explain your reasoning and why even Ford didn't need the third fuse to protect the circuit.
its all your fault :P, your earlier post i refered to was bugging be because you were dead right.
You were an ET and i was an AT in the navy, so that makes sense you have a lot to offer here.
here is what i did in the wee hours, i jumped on this adjustment because i seem to be able to clearly think in the early hours. My work schedule is odd anyway.
I had the time at that moment to piddle while i waited on a call from some of my guys on a job site to support them. I bonded the input of the coil down stream of the blower moter leg, it really didnt matter to me but since you brought it up, i thougth it was a good idea to "feed" the coil upstream of the blower instead.
The point you made about the OEM fused lead to the heater function selector switch was valid, i flipped open the fuse panel layout and decided its needs a 15A fuse back in because this fuse is source for many many other sub systems. ~valid point you caught again.
The reason i added a symbol for a fuse on the top main input of the resistor bank is this.....
While in low, we have the thermal limiter in play for protection.
WHile in M1 & M2, i noticed at the last minute that there was no protection down stream of the inductive motor load and felt "why not", lets put a fuse there. In effect anything downstream of the blower would have protection. I am not satisfied with the over current protection sizes on any of these relay mods we have been working on thus far and for no other reason than a whim, i am just generically tossing in a 30A with the intent that a "low voltage" event "could" be real when a failure is in process. Normal current draws would certianly go up says ELI the ICE man.
are we good ? and to both of you does this option work to your satisfaction? it hopefully replicates the explorer layout and again, i am glad we took our time to get this done.
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 17, 2012, 12:12:44 AM
Post by: jcassity on August 17, 2012, 12:12:44 AM
crazy 88,
your second bullet you posted above on post 34 finally sunk in, again valid point so i will say the thank you.
Bonding the input to the relay coil of K2 where i have it now is where i intended originally and now i see that the way it is drawn now for a ref wiring diagram is correct.
so,, you happen to be right about a lot but in the end good team work.
your second bullet you posted above on post 34 finally sunk in, again valid point so i will say the thank you.
Bonding the input to the relay coil of K2 where i have it now is where i intended originally and now i see that the way it is drawn now for a ref wiring diagram is correct.
so,, you happen to be right about a lot but in the end good team work.
Title: Protecting your blower motor switch (non-EATC)
Post by: Crazy88 on August 17, 2012, 12:32:26 AM
Post by: Crazy88 on August 17, 2012, 12:32:26 AM
Yeah Scott everything is fine, no worries.
If I recall correctly, your last revision and Quietlef's are virtually identical, schematically speaking. As for the inclusion of F3 for some protection against inductive motor load, I assume that you are referring to the current surge by a collapsing inductive field. A fuse is not a valid method of protection in such a case, as the amount of current surge induced in typical DC motor would be far less than required to open F3, and would be completed by the time the fuse could react, assuming that the current would be high enough to trigger protection in the first place. Milliseconds of higher than normal current, while certainly undesirable, are not something, in this case to be worried about. We are attempting to protect a switch from excessive long term heat rather than a few milliseconds of high current with no voltage potential and some fairly high wattage resistors... oh yeah and ground. ;)
If you have a spare few moments, can you elaborate on the other circuits that F1 is providing protections for? What is their total current draw? For that matter, is F2 a new fuse? If so, what is the current draw of the motor in high? Add about 500mA for the two relays (assuming Bosch 30A) and then we can size that F1 and F2 to actually protect the circuits.
If I recall correctly, your last revision and Quietlef's are virtually identical, schematically speaking. As for the inclusion of F3 for some protection against inductive motor load, I assume that you are referring to the current surge by a collapsing inductive field. A fuse is not a valid method of protection in such a case, as the amount of current surge induced in typical DC motor would be far less than required to open F3, and would be completed by the time the fuse could react, assuming that the current would be high enough to trigger protection in the first place. Milliseconds of higher than normal current, while certainly undesirable, are not something, in this case to be worried about. We are attempting to protect a switch from excessive long term heat rather than a few milliseconds of high current with no voltage potential and some fairly high wattage resistors... oh yeah and ground. ;)
If you have a spare few moments, can you elaborate on the other circuits that F1 is providing protections for? What is their total current draw? For that matter, is F2 a new fuse? If so, what is the current draw of the motor in high? Add about 500mA for the two relays (assuming Bosch 30A) and then we can size that F1 and F2 to actually protect the circuits.
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 17, 2012, 01:19:51 AM
Post by: jcassity on August 17, 2012, 01:19:51 AM
just download the respective EVTM pages in my link below. that should get you started.
Im not gonna taket the time to clamp the ampacity draw on F1 at this time, frankly F1 could be sized a little or a lot lower depending on what you prefer as in what conditions or faults you want to factor in the engineered design.
Actually f2 should be something along the lines of approx 10A auto circuit breaker over current protection device but i just stuck a fuse there for no other purpose than to illustrate protection. If you dont think it needs ot be there then its a user choice i would think.
"F3" we could assume is the thermal limiter and this is typically faulty in many peoples cars now because its open, they get High only.
i have not clamped on the motor load in high either.
They are not identical for the reason you pointed out. In his, i see the switch is still in play and carrying current because it is upstream of the resistor bank.
This does not match up to the Explorer layout so in effect, the latest revision i show places the switch in question on the ground end of the whole circuit so there is no current draw at all "if" the contacts are not pitted or causing a small load.
trust me ,, i actually considered three breakers for the speed control "if" leaving the existing wiring as is and using those circuits to power a relay.
If you look back, it was implied that the intent was to totally bypass the speed switch complely during "high" only.
Im not gonna taket the time to clamp the ampacity draw on F1 at this time, frankly F1 could be sized a little or a lot lower depending on what you prefer as in what conditions or faults you want to factor in the engineered design.
Actually f2 should be something along the lines of approx 10A auto circuit breaker over current protection device but i just stuck a fuse there for no other purpose than to illustrate protection. If you dont think it needs ot be there then its a user choice i would think.
"F3" we could assume is the thermal limiter and this is typically faulty in many peoples cars now because its open, they get High only.
i have not clamped on the motor load in high either.
They are not identical for the reason you pointed out. In his, i see the switch is still in play and carrying current because it is upstream of the resistor bank.
This does not match up to the Explorer layout so in effect, the latest revision i show places the switch in question on the ground end of the whole circuit so there is no current draw at all "if" the contacts are not pitted or causing a small load.
trust me ,, i actually considered three breakers for the speed control "if" leaving the existing wiring as is and using those circuits to power a relay.
If you look back, it was implied that the intent was to totally bypass the speed switch complely during "high" only.
Title: Protecting your blower motor switch (non-EATC)
Post by: Crazy88 on August 17, 2012, 01:51:22 AM
Post by: Crazy88 on August 17, 2012, 01:51:22 AM
Quote from: jcassity;396161
just download the respective EVTM pages in my link below. that should get you started.
They are not identical for the reason you pointed out. In his, i see the switch is still in play and carrying current because it is upstream of the resistor bank.
This does not match up to the Explorer layout so in effect, the latest revision i show places the switch in question on the ground end of the whole circuit so there is no current draw at all "if" the contacts are not pitted or causing a small load.
This is the last diagram revision posted by quietleaf this afternoon in post #31. He, like you edited his existing diagram, updating the post body with notes and replacing the diagram of course to reflect the changes. I hope that you will review this diagram and come to see that my buttstuffysis that the two diagrams are virtually identical schematically is also correct. There may be a few minor differences, but for the most part, they are more alike than different.
(http://www.foxtbirdcougarforums.com/attachment.php?attachmentid=30054&stc=1&d=1345154940)
Quote from: jcassity;396161
Actually f2 should be something along the lines of approx 10A auto circuit breaker over current protection device but i just stuck a fuse there for no other purpose than to illustrate protection. If you dont think it needs ot be there then its a user choice i would think.
Ok, I am confused again. Please tell me where in my last post I said that F2 was unnecessary? F2 is necessary, as this circuit is currently diagramed to provide protection to the secondary circuit, unless you were to tap F1 as the source voltage instead.
With regard to the circuit breaker, I wouldn't use a circuit breaker for this reason; the blower is a non-essential piece of hardware. The car will run fine without it and weather conditions not withstanding, can operate safely without the blower motor being operational. A semi critical system where I have see circuit breakers used might include semi-critical systems such as anti-lock brakes, head lamp circuits, hazard circuits, etc. In these limited cases, the limited functionality of a damaged circuit is preferred to operating without the semi-critical circuit.
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on August 17, 2012, 10:41:15 AM
Post by: jcassity on August 17, 2012, 10:41:15 AM
nah, they both are different with respect to the location of the speed control switch.
both are workable and simple
lets let these examples cycle for a few days then one of us can request a sticky, then get it over to eric for the tech section of coolcats.
the oem fuse feeding the heat selector switch is already called F9, my discussions have only pertained to the adder circuit, yes a misunderstanding.
tune up whichever drawing to illustrate your technical input so no one burns down thier car :)
both are workable and simple
lets let these examples cycle for a few days then one of us can request a sticky, then get it over to eric for the tech section of coolcats.
the oem fuse feeding the heat selector switch is already called F9, my discussions have only pertained to the adder circuit, yes a misunderstanding.
tune up whichever drawing to illustrate your technical input so no one burns down thier car :)
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on September 05, 2012, 11:23:51 PM
Post by: Quietleaf on September 05, 2012, 11:23:51 PM
It's been a while on this subject...where did we leave it?
On an off-topic note, I've been fighting the temptation to get one of these... (http://"http://www.liquidware.com/shop/show/TSL/TouchShield+Slide") I already have an Arduino Duo, and I have an LED voltmeter in the spot where the T/C ride control switches go. But it would be REALLY cool if I had a touch-sensitive display that could show volts, with a tach bar at the top, compass heading, outside temp, etc. Unfortunately I already have too many projects in the queue.
On an off-topic note, I've been fighting the temptation to get one of these... (http://"http://www.liquidware.com/shop/show/TSL/TouchShield+Slide") I already have an Arduino Duo, and I have an LED voltmeter in the spot where the T/C ride control switches go. But it would be REALLY cool if I had a touch-sensitive display that could show volts, with a tach bar at the top, compass heading, outside temp, etc. Unfortunately I already have too many projects in the queue.
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on September 11, 2012, 02:10:52 PM
Post by: jcassity on September 11, 2012, 02:10:52 PM
take it from the top,,
I like my option a tad more than yours because there is less of everything so to speak to do.
However, also compare yours to mine and like crazyman said, they both will work.
Im glad i noticed this thread, its on my radar for EATC systems,, "if" its even needed.
I like my option a tad more than yours because there is less of everything so to speak to do.
However, also compare yours to mine and like crazyman said, they both will work.
Im glad i noticed this thread, its on my radar for EATC systems,, "if" its even needed.
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on September 11, 2012, 02:16:19 PM
Post by: jcassity on September 11, 2012, 02:16:19 PM
my version on page 4 post 33
, yours also resides on page 4, either way both great solutions.
, yours also resides on page 4, either way both great solutions.
Title: Protecting your blower motor switch (non-EATC)
Post by: TOM Renzo on September 12, 2012, 06:17:38 AM
Post by: TOM Renzo on September 12, 2012, 06:17:38 AM
J what if you were to reverse the speed switch from controlling ground to controlling battery and use a relay for high speed. Fan motors draw less current at reduced speeds and by controlling the high speed battery feed with a relay is in my view better than controlling the ground to vary speed. I know you are going to hammer me on everyone does it this way. But for years it was dun the other way around. Just saying. Thanks
Title: Protecting your blower motor switch (non-EATC)
Post by: Quietleaf on September 12, 2012, 10:58:59 PM
Post by: Quietleaf on September 12, 2012, 10:58:59 PM
Quote from: jcassity;398020
my version on page 4 post 33
, yours also resides on page 4, either way both great solutions.
It's been a while since I was looking at these. Is the only difference in the way the pins are arranged on the resistor and the 30A fuse above it?
At this rate we'll be rewriting the EVTM :D
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on September 13, 2012, 04:52:01 PM
Post by: jcassity on September 13, 2012, 04:52:01 PM
Quote from: TOM Renzo;398082
J what if you were to reverse the speed switch from controlling ground to controlling battery and use a relay for high speed. Fan motors draw less current at reduced speeds and by controlling the high speed battery feed with a relay is in my view better than controlling the ground to vary speed. I know you are going to hammer me on everyone does it this way. But for years it was dun the other way around. Just saying. Thanks
thats actually what the original evtm page does but "we" want to remove the wattage disipation from the switch and putting the speed switch in series with the ground means there is little or no current across the speed select switch.
Again, i have hacked this diagram up and it looks totally different from the same EVTM page number you can access in my diy link below. If we do that (what your saying) we would actually defeat the purpose of the thread, as an example supplied by quietleaf, the newer explorers "switch the ground leg"
Title: Protecting your blower motor switch (non-EATC)
Post by: jcassity on September 13, 2012, 04:53:14 PM
Post by: jcassity on September 13, 2012, 04:53:14 PM
Quote from: Quietleaf;398145
It's been a while since I was looking at these. Is the only difference in the way the pins are arranged on the resistor and the 30A fuse above it?
At this rate we'll be rewriting the EVTM :D
three things change....
repin the speed switch
repin the blower resistor pack
add new isolated power source for "HIGH" only.