Headlight relay ???

[PanelDeland]

I'm planning on doing the hedlight relay upgrade.Here are the questions I have.

1.Are the connectors in the Bulkhead connector on the firewall all the same?I'm wanting to run the Green and Tan wires new all the way from the firewall so I don't have any splices.
1a.What size wire?I'm thinking 14 ga or above will be plenty.
2.Is there any advantage to running a relay on the Park lights/Turn signals?I'm thinking the draw is small enough to not make much difference.
3.Is a #10 wire guage overkill to feed the power to the relays?
4.Should I upgrade the power wire from the battery to the Main power block on the inner fender?
5.I read a couple of threads but didn't see what the fuse shuld be rated at.

[VetteVet]

.....

Originally Posted by PanelDeland

I'm planning on doing the hedlight relay upgrade.Here are the questions I have.

1.Are the connectors in the Bulkhead connector on the firewall all the same?I'm wanting to run the Green and Tan wires new all the way from the firewall so I don't have any splices.

The connectors are not wired the same but all you have to do is make sure you plug the tan and green wires into the same holes they were in. These wires are run all the way from the connector to the left headlight so how much more wire do you need?

1a.What size wire?I'm thinking 14 ga or above will be plenty.You don't need any bigger wires because all they are going to do is power the relays and that takes less than an amp.

2.Is there any advantage to running a relay on the Park lights/Turn signals?I'm thinking the draw is small enough to not make much difference. Not worth the trouble

3.Is a #10 wire guage overkill to feed the power to the relays? All the stock trucks used 14 and 18 to burn the headlights and that includes the Tan and green wires from the firewall connector. I think 12 ga. is plenty unless you're running Halogens or HIDs then I'd run 10s. You get some voltage drop with the old stock wires but the length of them plus the small size caused that. When you wire the relay power to the headlights, the shorter wires and bigger sizes eliminates the voltage drop. There are charts to show the voltage drop on a given length and size wire with a set current draw and they show how much voltage you lose for a given size and length. I may have one.

4.Should I upgrade the power wire from the battery to the Main power block on the inner fender? Yeah take it up to a 10ga and use a 40 amp maxi-fuse slow blow in place of the fusible link.
5.I read a couple of threads but didn't see what the fuse shuld be rated at. 20 amps is the common size

Here is a diagram for the chevy's The white and yellow wires are really the tan and green on the truck.



Here is one for the GMC's

[Wrenchbender Ret]

#1 yes
#1a 16-18 gauge is all you need.
#2 No need
#3 12 gauge is big enough.
#4 good idea
#5 Use a fuseable link. Do not put a fuse in the headlights.

[PanelDeland]

Tanks Wrenchbender,I pretty much thought I was close to what was right,just wanted confirmation.I think you're right about the 16-18 a relay coil wont pull much.

[Bigb401]

Why a fuse able link and not a fuse?
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[storm9c1]

Originally Posted by Bigb401

Why a fuse able link and not a fuse?
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Safety (and liability if you are GM). You don't want a fuse heating up and blowing randomly on a dark country road. A fuse can fail just with age if it is pushed anywhere near their limit for extended periods of time. Due to the nature of the filament, they can also draw much more current at startup versus steady burning. And this can also blow fuses, especially when blinking your lights or switching from high to low beams.

The safest thing to use is a self-resetting (quick reset) circuit breaker. That is what the factory preferred for many years and typically included one inside the headlight switch itself. Instead of a fusible link, if you really want to use a fuse, I guess it would be OK to overrate the fuse by 50-100% to help make it more reliable (since a fusible link will be ridiculously overrated as well). But if it were me, I'd use a self resetting breaker.

[Bigb401]

Ya ok. I'm gonna be doing the upgrade to and was thinking a breaker or fuse, and like you said, fuse it at 50 to 100%. There are pros and cons to both. But I really dont like the idea of a fusable Link under the hood. I just wanted your opinion and any other reasons. Thanks storm
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[VetteVet]

Did my post no. 2 not show up?

[PanelDeland]

It has now VV.Thanks.