Wiring up off road lights with a relay for a light bar

Jeep Addict

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Baton Rouge
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I’m wiring up some fog lights on my windshield and the factory doesn’t use a relay. I want to use a relay. The factory fogs are designed to get power from the low beam switch and automatically turn off when you turn on your highbeams. I want to draw power directly to the fog switch. My question is can I wire the relay 30 and 86 to the same power source together into the 15 amp terminal from the first photo?DA52F9FE-1637-4659-8585-E3D6EB467041.png504090D1-914C-4491-8CD3-989D0FA98FE0.png
 
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Randyzzz

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I’m wiring up some fog lights on my windshield and the factory doesn’t use a relay. I want to use a relay. The factory fogs are designed to get power from the low beam switch and automatically turn off when you turn on your highbeams. I want to draw power directly to the fog switch. My question is can I wire the relay 30 and 86 to the same power source together into the 15 amp terminal from the first photo?View attachment 91668View attachment 91669
Yes, you can but that means the lamps can be turned on at any time. I prefer to wire 30 to the battery as shown, and wire 86 to an ignition controlled power source. That way when I turn off the ignition the fog lamps turn off also. The draw from terminal 86 is minimal- so you can tap into almost anything.
 

bigwalton

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If I understand you, you want to power the relay and lights off that terminal in the fuse block. That seems ok as long as you’re adding a fuse between the terminal and the relay/lights (as they add in the first photo with the 20A fuse holder.)

But I’m not understanding your comment “I want to draw power directly to the fog switch.” Because your second diagram is showing a switched negative to trigger the relay. There wouldn’t be “power” at the switch, you’d just ground it. When the switch is on, the relay has ground and the lights come on.

If you’re wanting to keep the function of the fogs turning off with the high beams, then you have to have the 86 feed coming from the low beam switch. (As I read it, that’s a 12V feed unless the high beams are on)

I’d probably run the relay under the hood with the power straight from a fuse from the battery and just use the relay 12v feed from the low beam switch and ground trigger from your fog light switch.

I think that gets you everything you want in the cleanest way.
 

bigwalton

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Yes, you can but that means the lamps can be turned on at any time. I prefer to wire 30 to the battery as shown, and wire 86 to an ignition controlled power source. That way when I turn off the ignition the fog lamps turn off also. The draw from terminal 86 is minimal- so you can tap into almost anything.
I was reading it as wanting to keep the factory function of turning off with high beams.

Good point on considering if the lights could be left on with the ignition off.
 

Jeep Addict

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Baton Rouge
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La
My Jamboree came with the OEM light bar lights. The factory wiring under the dash was still there but the wiring around the bar itself was hacked. I have a nos wiring harness that I’m going to replace the hacked wire with.

The original relay had a power wire going to the cruise terminal and the original light bar lights switch had a power wire going to the radio terminal. They were wired to each other and the ground and the light bar. No inline fuse.

I am going to power the CB radio from the radio terminal so not using that terminal for the lights.

My plan was to use a factory jumper wire that I have that would connect 30 and 86 together on the relay and get power from the cruise terminal. This would run back to the power on the fog switch with and include a inline 20a fuse.
Then 87 to lights and 85 to ground.
End goal is to have the light bar work with high and low beams. I‘d like to run a relay since that‘s how it was originally wired.

I’m just pissing in the wind at this point but hopefully got my point across.
In my mind the top wiring diagram in the next picture is what I’m getting atF1FD8FA8-763B-4F1E-BA86-A2B78D7A8C1B.pngBB76BB6D-F843-4D47-AC82-0ED7287007ED.png
This picture just shows radio and cruise terminals that relay and light bar were plugged into.

Once I figure this wiring out I am adding the same light bar set up to yard Scrambler and another Jambo.
 

FLCJ8

Legacy Registered User
City
Palm Bay
State
FL
I'm going to throw my two cents in to confuse things a little more...

By your description of the factory wiring the power to the relay coil via the switch was powered and protected by the radio fuse. This would afford the protection that Randyzzz mentioned of protecting the lights from running the battery down when the ignition switch is "OFF"

The ground connection on your original factory pic is for the ground connection for the indicator lamp in the switch.
The switch typically controls the +12 vdc to the fog lamp relay coil.

Does your switch have the indicator light, and does it light when the fogs are energized or when the low beams are on?

The FSM wiring diagram seems to indicate that the indicator light illuminates whenever the low beams are "On" and the fogs are available for use.
(I don't know if this correct or not, or whether your switch has an indicator light.)
I would think the light should only illuminate when the fogs are actually "on".

Anyway, I attached a snip of the wiring diagram for an '82/'83 that may or may not help:
Fog.PNG
 

bigwalton

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My Jamboree came with the OEM light bar lights. The factory wiring under the dash was still there but the wiring around the bar itself was hacked. I have a nos wiring harness that I’m going to replace the hacked wire with.

The original relay had a power wire going to the cruise terminal and the original light bar lights switch had a power wire going to the radio terminal. They were wired to each other and the ground and the light bar. No inline fuse.

I am going to power the CB radio from the radio terminal so not using that terminal for the lights.

My plan was to use a factory jumper wire that I have that would connect 30 and 86 together on the relay and get power from the cruise terminal. This would run back to the power on the fog switch with and include a inline 20a fuse.
Then 87 to lights and 85 to ground.
End goal is to have the light bar work with high and low beams. I‘d like to run a relay since that‘s how it was originally wired.

I’m just pissing in the wind at this point but hopefully got my point across.
In my mind the top wiring diagram in the next picture is what I’m getting atView attachment 91671View attachment 91672
This picture just shows radio and cruise terminals that relay and light bar were plugged into.

Once I figure this wiring out I am adding the same light bar set up to yard Scrambler and another Jambo.

Now I get it, losing the auto-off with the high beams makes it much easier (and I never understood why it needed to happen anyway.) I like your solution for what you say you want.

(That diagram of the fuse block is great and I think it will help a lot of other folks not good at reading wiring diagrams. Going to steal it and post in a thread of its own.)

My only question, which FLCJ8 asked about, is illumination for the switch. If it does light up, you have to think about the setup to make that work in the right conditions. Sounds like it would just take an extra ground to the fog light switch for the light, if needed, since you're talking about having the switch on the power side of the relay trigger.
 

Randyzzz

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If you pull your power for terminal 86 from your parking light circuit, the fog lamps will operate in conjunction with both high and low beam. Since the lamp circuit is not ignition controlled, you can still drain your battery by accidentally leaving your lights on. I like adding a “lights on” buzzer with a small toggle to override in case I really do want the lights on with the key out.
 

Jeep Addict

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Baton Rouge
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Long story short I have no clue what I'm doing, LOL. I just google searched a bunch of relay diagrams and in my mind chose the one that best fit what I am trying to do.

I don't even know if the windshield light bar had the auto-off feature since technically it's an "off-road" light and the FSM show's the setup being wired to the cruise control terminal, ground and lights only. Which is how I have it hooked up now.

I could simply leave it hooked up the way the FSM shows and not use a relay. I'd like to run the relay from keeping all of the power from running through the switch and possibly burning up anything.

The switch is the OEM switch and does have the indicator light. I did bypass the relay and wired the switch directly to the fuse panel, lights and ground. It worked as it should. The fog lights came on and the switch did illuminate when it was on.

I just checked another CJ with the factory front bumper fog lights. The switch only illuminates when the headlights are on and low beam only. It is hooked up through the factory harness

Steal and post any diagrams. Hopefully they will help someone else.

Does it matter what whether I hook the switch to the power or ground side of the relay trigger for the light bar?

I plan on doing a mock set up before to test it out before I wire in the Jeep.
 

Randyzzz

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You can use switch power or ground to trigger the relay, whichever works better in your install.

I just got through adding fog lamps and a light bar (switch only so far) to my XJ. I overthought/over engineered that a bunch. But it all works! I was having so much fun, I made a trailer light converter out of relays too!
 

bigwalton

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Run the relay for sure and Randy covered the switch, doesn’t matter how you run it.
 

MomoJeep

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Seattle
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WA
BTW - if these are really "fog" lights... Fog lights are designed to shoot out a beam that is low to the ground, underneath your line of sight, and are recommended to be mounted somewhere underneath your headlights.
 

BRKLYNZ28

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BROOKLYN
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NY
Isn't the correct jambo switch ganged on top of each other .
 

Jeep Addict

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Baton Rouge
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La
Isn't the correct jambo switch ganged on top of each other .
I’ve seen the export models with rear fog lights have the stacked switch. The Jambo brochure shows two individual switch housings if you look close. I know of only one Jambo owner that had factory light bar and brushguard lights and there were two individual switches when purchased new.
 
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