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headlights..intermittent power???

2861 Views 31 Replies 12 Participants Last post by  sucker4jeep
so my headlights will occasionally turn off and on. i was going to just install a toggle switch and delete the dimmer but there are 4-5 wires coming out of the harness(im sure they have to do with dash lights etc.) . how can i wire them all to come on or off with a simple toggle?
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I have heard that once the Circuit breaker inside the headlight switch starts to trip, it trips more often.
If the parking lights and dash lights go off at the same time the headlights go out, then it is your circuit breaker that is tripping and not a bad connection.
It all the lights go out, there may be another short someplace.
 

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Replaced the dimmer. Not the problem. So, I started wiggling wires all along the circuit, again. It looks like the ground may be a problem at the driver side pigtail. I had replaced the pigtail, but maybe the location of the ground is not strong enough. So moved the ground. Let's see if that is the problem.
 

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I have heard that once the Circuit breaker inside the headlight switch starts to trip, it trips more often.
If the parking lights and dash lights go off at the same time the headlights go out, then it is your circuit breaker that is tripping and not a bad connection.
It all the lights go out, there may be another short someplace.
Only the headlights are intermittent, so not the switch. Even if the wire to the switch was loose, I think the running lights would turn on and off, but they don't.
 

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So you have checked for consistent power out at the floor dimmer switch?

If so, I would then work forwards along the wires to the headlights.

The dimmer switch is not grounded, but the headlight bulbs are. The main ground for the headlights is at the headlights. This is not an aircraft, so cheapest way ruled. The ground is probably to the radiator grille, which connects to the fender, which connects to a ground strap that connects to the engine, that connects to the battery (or something like that). Not unheard of for somewhere along that path to get a break. A good upgrade is ground conductors of equal size to the supply side of the circuit, and taken back to the battery or a central grounding point.

These are the panel lamps, they are all grounded locally to the lamp. You will note inside the light switch is that pesky thermal breaker.

Schematic Font Parallel Engineering Plan

1977 Wiring


Rectangle Schematic Font Parallel Slope


1980-1983 wiring (sorry, written over it)

Schematic Rectangle Font Engineering Parallel
 
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Headlights are definitely brighter using an alternate ground than the stock one, but not fixing the intermittent problem. I think I need to trace the wire to see if the casing is rubbed off somewhere and it is shorting?
 

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So you have checked for consistent power out at the floor dimmer switch? (will check with the multi-meter. Just used the touch light.)

If so, I would then work forwards along the wires to the headlights.

The dimmer switch is not grounded, but the headlight bulbs are. The main ground for the headlights is at the headlights. This is not an aircraft, so cheapest way ruled. The ground is probably to the radiator grille, which connects to the fender, which connects to a ground strap that connects to the engine, that connects to the battery (or something like that). Not unheard of for somewhere along that path to get a break. A good upgrade is ground conductors of equal size to the supply side of the circuit, and taken back to the battery or a central grounding point.

These are the panel lamps, they are all grounded locally to the lamp. You will note inside the light switch is that pesky thermal breaker.

View attachment 4173802
1977 Wiring


View attachment 4173803

1980-1983 wiring (sorry, written over it)

View attachment 4173804
 

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If the wire was rubbing, it would be shorting. The thermal breaker at the headlight switch would be heating up and you will see the dash lights blink.

Possible you have a loose connector or a broken wire. Wires can break inside the insulation, which is why you have to be methodical in testing.

Sounds like your grounds are an issue anyway.
 
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If the wire was rubbing, it would be shorting. The thermal breaker at the headlight switch would be heating up and you will see the dash lights blink.

Possible you have a loose connector or a broken wire. Wires can break inside the insulation, which is why you have to be methodical in testing.

Sounds like your grounds are an issue anyway.
Yes, I've rewired the rest of the engine compartment. I guess I'll rewire the lights. That should fix it.
 

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Order something like this while you're at it for an even "better Headlight experience", lol:

H4 9003 Headlight Relay Wire Harness Kit for 7x6 5x7 H6054 Headlights Heat Ceramic Wiring Harness Fit for Tacoma 95-97 and Suzuki Samurai,Fix Dual Ground Problem https://a.co/d/0Urlqau
 

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I had the exact issue you described a few months ago. Figured it was the floor dimmer as stated by several in this thread, but wasn't. I pulled the actual headlight switch out and removed all the wires. The main power feed was black and melted. Its the thicker red wire, possibly with white tracer. Either way, youll notice right away. Had to buy a new headlight switch and redo the power feed connector as it was melted so badly. I also did the relay upgrade and HIGHLY recommend it. Tons more light and no more placing the heavy load on the headlight switch.
 
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