Fail safe relay wiring

Topic: Fail safe relay wiring (Read 2183 times) previous topic - next topic

Fail safe relay wiring

January 05, 2013, 10:49:21 PM

Thunder chicken can i post my fail safe wiring diagram and redundant relay wiring for you and others to see it works? Thanks!

Fail safe relay wiring

Reply #1 – January 05, 2013, 10:59:03 PM

thunderchicken is in canada
you are in the usa,, depending on where the message board is based, it might be in this free country,,, lol why you ask?

id say anything to help logivity of these cars is what its all about,,,, i try so hard to make sure mine are as stock as possible,,, even down to those little lables and such but time marches on.

Fail safe relay wiring

Reply #2 – January 05, 2013, 11:56:24 PM

Jay he warned me about my posts so i am getting permission. He said my wiring wont work. So i nave it mocked up and want to post it. So i am asking permission. He owns the board and forum so i want permission Thanks.

Fail safe relay wiring

Reply #3 – January 06, 2013, 07:56:36 AM

That's it, Tom... Poke the hornet's nest...

Go ahead and post your redundant relay setup. I didn't say your wiring wouldn't work, I said that the way you had it in that drawing wouldn't work. There would be no way to turn it off if wired like that drawing.

Fail safe relay wiring

Reply #4 – January 06, 2013, 09:21:33 AM

IGNITION SWITCH OFF no power to the load light off

Ignition switch on power fed through the slave relay AUX BATTERY Not through the ignition switch Ignition switch powers up relay coil aux battery supplies load

Coil failure in relay ignition switch supplies load.

WHEN THE IGNITION SWITCH IS OFF THERE IS NO BATTERY FROM EITHER SOURCE TO THE LOAD.

REDUNDANT BATTERY FEED FROM 2 DIFFERENT SOURCES

THIS I USE IN ALL MY CIRCUITS TO AVOID A RELAY FAILURE AND NEED OF A TOW TRUCK

THANK YOU FOR LETTING ME POST IT THUNDER HERE IT IS WORKING EXACTLY AS I EXPLAINED. YOU PROBABLY DID NOT UNDERSTAND WHAT I DID OR HOW IT WAS WIRED. NO PROBLEM I WAS TAKEN BACK BY YOUR POST AS SAYING IT WOULD NOT WORK. THANKS AGAIN

Fail safe relay wiring

Reply #5 – January 06, 2013, 01:38:17 PM

here is an etch and sketch of what you show wired and when...
i am fairly certain i have it drawn wrong, pls confirm,,, i only attempted to draw what i saw was bonded to where.

Fail safe relay wiring

Reply #6 – January 06, 2013, 04:01:22 PM

Jay reverse pins 87 & 87a then you have the circuit!

Fail safe relay wiring

Reply #7 – January 06, 2013, 04:30:42 PM

Ok, drawn that way I can see how it works. Still can't see the point of it in an automotive application (maybe on an airplane, where if something fails it's a 30,000 foot boo-boo so a Plan B is a necessity), but I can see how it would work.

And before you fly off the deep end, Tom, I say I can't see the point of it because virtually every car made since the mid 80's relies on at least one relay to run, and I can't think of any that have that redundancy wired in. Yes, relays fail occasionally, but not at a rate that redundancy is required - for every fuel pump relay that fails there are eleventy-two bazillion relays that don't. The load the relay is powering is actually more likely to fail than the relay itself (IE you're more likely to need a fuel pump than a fuel pump relay, and your headlight bulb is more likely to burn out than the relay feeding it). The redundancy would do no harm, but it also does very little good. Indeed, the most common cause of relay failure, at least in GM cars, is not the relay itself but the terminals it's plugged in to (they usually overheat and burn up), and in this case redundancy wouldn't work because the power would still have to pass through those terminals. In other words it's that thing you accuse everyone else of doing: Overkill.

Fail safe relay wiring

Reply #8 – January 06, 2013, 04:46:22 PM

Sorry you don't like it Thanks

Fail safe relay wiring

Reply #9 – January 06, 2013, 05:17:16 PM

ooppsie

ok , rearranged the lables and terminations

are you sure its ok to pass high current through the contacts *and* the coil of the relay.? i am against this, you should blow the coil out quick.

are you using the term in post 1 "LOAD" lamp in direct relation to automovtive loads? by using the white wire as your "load wire"

sorry i dont get it ,,,,,,,,,,,yet,,,,,,,,, but im sure you can explain.
in the middle "energized state" i show a green arrow for power path.

if this is a slave relay circuit isolation where heat is no longer on the switch and its a fail safe, i see no way for power to get out if the coil were to open.

Fail safe relay wiring

Reply #10 – January 06, 2013, 06:55:25 PM

NO NO the white wire is the coil pull in lead. Along with the black. Blue Red & yellow are the contacts

Blue 30
Red 87a
Yellow 87

Thunder Chicken posted it was a lot of extra wiring but in actuality it is just one more lead that is already on the connector. As far as the relay going bad that is true they are reliable. But they do go bad. As the matter of fact the new relays coming from wherever have been built quite shabby lately. With that i proved it works and that was all i wanted to do. So wire stuff any way you see fit.

Thunder here is an ATC universal fuse holder. It is rated at 30A. As you can see it failed with a 20AMP fuse. This is the they sell. I had a long talk with my vendor about this foreign junk. So dont think relays are any different just saying!

Fail safe relay wiring

Reply #11 – January 06, 2013, 07:59:35 PM

Well, going by what you're saying the morning commute is really gonna suck, what with dodging those tens of thousands of broken down cars all over the roads. Guess I'll be lucky if I even get there myself, since all three of my vehicles rely heavily on relays for their very survival. And there but for the grace of God and a bunch of failed relays go I... Shoulda just bought a horse instead

Fail safe relay wiring

Reply #12 – January 06, 2013, 10:37:35 PM

so the diagram i drew would not be how its installed in the vehicle,,,,,?

tc~ also buy snacks~!

Fail safe relay wiring

Reply #13 – January 07, 2013, 06:00:07 AM

Jay just swap the 87 with 87a and you are golden.

Fail safe relay wiring

Reply #14 – January 07, 2013, 06:21:38 AM

But was this thread not because of an engineering flaw in our vehicles. Just saying. When designed i think FORD did not count on components failing and or burn connectors and switches. Seems like people on this site have to slave out a hell of a lot of switches and controls or replace ignition switches that have failed and burnt these cars to the ground. They were also recalled for the issues. If memory serves me you made an elaborate circuit pack for your car for the issues. So clearly you understand the issue with this. I have my thoughts on things and so do you. Either way we fixed the issues just differently and that is fine.. Bottom line if cars dont break neither of us have to worry about commuting !! Thanks for listening and allowing me to post . .