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Topic: Relay modification Headlamp and Marker lamp *pls review (Read 6265 times) previous topic - next topic

Relay modification Headlamp and Marker lamp *pls review

Lets all put eyes on this and approve before calling it good for the board.
Purpose:
Redirect the wattage/heat displacement tyically experienced by the headlamp switch & heat sync.
Reduces heat on the headlamp switch connector.
Increases life span of OEM switch and reduces chance of electrical problems as a result of excessive heat effects experienced by the OEM design.

Source drawings are from the 1987 EVTM
If the pins/wire colors are consistent for 1988EVTM and the 86 and earlier years, then the "generic" intent stands well.

Headlamp mod ~ intercept the wiring as shown, apply power and ground.

Exterior lamp mod ~ decided to stay with same concept so intercept wiring as shown, intercept existing over current protection , apply a ground as shown.
 

Relay modification Headlamp and Marker lamp *pls review

Reply #1 –
Looks like it would work fine to me.  I wonder what the current draw through the head lamp switch would be after the modification?

Relay modification Headlamp and Marker lamp *pls review

Reply #2 –
all other devices such as cluster lighting, ,,,could be as low as 5A at the very very most.

Relay modification Headlamp and Marker lamp *pls review

Reply #3 –
Looks good to me. Also has the advantage of not overloading the headlight switch if you have factory fog lights.

I did mine differently, having access to a cop car fuse/relay box. I had six relays: one for high beam, one for low beam, one for each fog light, and two extras that I was going to use to integrate daytime running lamps into the system (Nova Scotia law requires them but I never got around to adding that functionality, instead using the fog lights, which were wired to come on with the ignition as a stop-gap measure to meet the law). Here's how I had that wired (the "To Battery" wires are wired into the integrated fuse panel, shown in the photo). The headlight switch still carried park light current, but it was my plan to replace all running lights with LED's...
X
The white relays in the photo below were going to be the DRL relays:
X
And the fuse box covered up, for a nice factory look (this fuse/relay box was a Ford part):
X
2015 Mustang GT Premium - 5.0, 6-speed, Guard Green - too much awesome for one car

1988 5.0 Thunderbird :birdsmily: SOLD SEPT 11 2010: TC front clip/hood ♣ Body & paint completed Oct 2007 ♣ 3.55 TC rear end and front brakes ♣ TC interior ♣ CHE rear control arms (adjustable lowers) ♣ 2001 Bullitt springs ♣ Energy suspension poly busings ♣ Kenne Brown subframe connectors ♣ CWE engine mounts ♣ Thundercat sequential turn signals ♣ Explorer overhead console (temp/compass display) ♣ 2.25" off-road dual exhaust ♣ T-5 transmission swap completed Jan 2009 ♣

Relay modification Headlamp and Marker lamp *pls review

Reply #4 –
i feel a sticky coming on,,,, good info Thunderchicken, glad you took a peek.
I also contemplated individual relays breaking out individual circuits.  Mason may want this in his bird so he'll be buying a fuse block on digikey.

Relay modification Headlamp and Marker lamp *pls review

Reply #5 –
Low and High headlights I can understand, but what is the intended benefit of having left and right fog lights on distinct circuits? Also mentioned was the fact that this fuse block is a Ford part, but would it be possible for Thunder Chicken to tell us the part number or the source of this particular item?

Relay modification Headlamp and Marker lamp *pls review

Reply #6 –
88 as i always say people over design circuits. TC has a nice setup their but totally over built. The fog lights do not draw excessive current that need 2 separate relays. And the HI LOW relay can be accomplished with one relay instead of 2. Once again an over designed circuit and way to much confusing wiring. Just me i make it simple!! The fog lights can be paired to one relay. And another relay for HI LOW and another to slave the headlight switch is all that is needed. And it all can be dun right at the switch and not under the hood. As the wiring is adequate as built.

I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

Relay modification Headlamp and Marker lamp *pls review

Reply #7 –
Tom,
Can you comment on the slave relay applications and tell us if you see a problem with either layout.

Relay modification Headlamp and Marker lamp *pls review

Reply #8 –
I prefer two relay layout for headlamps too. Why? Because you can use existing head lamp wires to trigger those two relays (one for low beams and one for high beams). Power for them can be connected directly to the battery (and fuse) to prevent voltage drop on the cables and switches. In fact you can use one relay version, but I don't see any bigger difference, because you must have another relay somewhere to power up the headlamps. Why? Because standard relays aren't three state (off/lo/hi), they are just two state (Lo/Hi). If you delete the relay for powering this switch relay, you lose the advice of small voltage drop. I measured it couple weeks ago and it did over 2 Volts difference on a car WITHOUT systems sentry!

One relay for both fog lamps is OK.

Relay modification Headlamp and Marker lamp *pls review

Reply #9 –
Trinom
Are you saying the relay should be downstream of the multi-function "hand lever" switch?
If so, i agree and its my belief now that the Hi-Lo relay fittment needs to be exactly there.

Relay modification Headlamp and Marker lamp *pls review

Reply #10 –
Rev1 13aug2012 below.
Pls review and approve prior to making it a tool for the board.
I placed the dual headlamp Hi/Lo beam relays downstream of the multi-function switch thus removing all heat possibilities from these switches.

This was the best i could do to keep the drawing neat and in tact with the existing overlay.

any thoughts?

X
X

Relay modification Headlamp and Marker lamp *pls review

Reply #11 –
I'm not definitely sure what exactly you are asking about, so I made a quick drawing. It's quite simplified, because flash to pass relay isn't important and number of bulbs isn't important either.


Circuit on the left shows the original circuit - no relays, just switches.
The circuit in the middle called "switch saver" shows one alternative - switches are just for trigering the relays, so the current flowing through the switch contacts is much lower, than in the original circuit. This version needs one relay for each switch. This design doesn't care so much about voltage drop on those long wires.
And finally the circuit on the right shows the most ideal modification and probably also the easiest one. It uses existing wires, which were originaly connected directly to the light bulbs. Instead of this, they are now connected to the relay coils and trigger the relays. Good place for the relays is next to the starter relay. The relay feeds come directly from the battery  which is very close to the headlamps (through the fuses for each relay, or one for both). This means, that the voltage drop on the wires from battery is much smaller, than in the original circuit. The result is in much brighter headlamps and also lower switch temperatures, which means longer life span.

PS: This is reaction on your previous post, not the last one. Unfortunately the internet connection fell down before I hit the submit button yesterday night.

Relay modification Headlamp and Marker lamp *pls review

Reply #12 –
Quote from: jcassity;395910
Rev1 13aug2012 below.
Pls review and approve prior to making it a tool for the board.
I placed the dual headlamp Hi/Lo beam relays downstream of the multi-function switch thus removing all heat possibilities from these switches.

This was the best i could do to keep the drawing neat and in tact with the existing overlay.

any thoughts?
That's exactly, what I call version two. The best place for those two relays is next to the starter switch. It's a quite dry and safe place, very close to the battery.

Only problem is, that it's not compatible with systems sentry's low beam out warning.

Relay modification Headlamp and Marker lamp *pls review

Reply #13 –
Ok has anyone actually tested the voltage drop in the headlights with the stock wiring??? I have and it nothing to worry about. And does everyone realize the draw down is only 6A low and 7 A high per lamp . Not exactly a candidate for a dedicated battery feed condition. I would suggest testing voltage drop before designing circuits that are over the top and messy as well. I slave the switch contacts which is needed because the switch is the issue and the week link in the system not the wiring. And it does not interfere with FTP. It has it's own relay .  if connected properly.  Its neat clean and simple. Basically we are talking about a device that draws small amounts of current in comparison to other devices. Dont over-design circuits. It complicates it and it adds way to much wiring and is not necessary. Just My $.02

Note you might want to reconsider the relay locations under the hoods. Here is why!!!

I spend money I don't have, To build  cars I don't need, To impress people I don't know

HAVE YOU DRIVEN A FORD LATELY!!

Relay modification Headlamp and Marker lamp *pls review

Reply #14 –
I used this information I was directed to when I had my 1997 Mercury Grand Marquis:

http://www.danielsternlighting.com/tech/relays/relays.html

I used crownvic.net a great panther forum.

There was a considerable difference in the brightness of the headlights after the upgrade!!