Wiring issue

[jakeh937]

Just bought a 79 CJ5. The previous guy said he went through and re did some of the wiring under the dash. I got it home and was messing around and noticed a few things.. first and foremost the high beams work. However when you hit the dimmer switch on the floor, the low beams come on for a second or 2 and then fizzle out. The dash lights flicker and you can hear and feel the electricity in the headlight switch. The switch looks new. I'm kind of lost here... is this a switch issue?

Another thing I noticed is the marker lights. I have no marker lights on any corner fender. Now I'm not sure if that's an issue related to wiring to and from the headlight switch or something else going on.

Lastly, the rear tail lights do not turn on unless the headlights are on. I thought when the dash lights come on (first detent) all the marker lights are suppost to come on?


I'm hoping this is an easy fix that someone has experienced. Thanks!


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[Torxhead]

I would suggest getting a wiring diagram for you vehicle:
https://colorwiringdiagrams.com/

 

[jakeh937]

I would suggest getting a wiring diagram for you vehicle:

https://colorwiringdiagrams.com/

Woah! Are those things pretty sweet?


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[jakeh937]

So for what it's worth.. the high beam circuit works fine. However, when I disconnect the connector from the hi/low switch and run power through a power probe on the low beam circuit, it pops the breaker in the power probe. I want to trace the wire, it's gray/black but I do not know where it goes.. any help??


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[jp360cj]

So for what it's worth.. the high beam circuit works fine. However, when I disconnect the connector from the hi/low switch and run power through a power probe on the low beam circuit, it pops the breaker in the power probe. I want to trace the wire, it's gray/black but I do not know where it goes.. any help??


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What is a power probe? Are you talking about a meter, or test light, or what?

What exactly are you doing to "run power through a power probe" (like power from which wire and connecting it to which wire)?

What is the breaker rated at that it's popping?

For the headlight circuit, the power goes from the light switch to the dimmer switch, then 2 separate wires go to the driver side headlight for high beam and low beam. I don't remember which wire is which. From the driver side light, the high and low beam wires jump to the passenger light. I think the headlights are 55w, so there is 5-6+ amps going through the light switch and dimmer switch. If you are trying to use a test light type probe in place of the dimmer switch to make the connection, then it's probably just too much current for the test probe. They are typically designed to be used in parralled where they "see" very little current, not in series where the full current passes through.

A quick test of the low beam circuit would be to use a jumper wire at the dimmer switch to go from the feed wire to the low beam wire. This will bypass the dimmer switch. If you have to redo any of the wiring, I would suggest adding relays and dedicated grounds to the headlights. It's pretty cheap if you do it yourself and the difference is amazing.

 

[jakeh937]

What is a power probe? Are you talking about a meter, or test light, or what?



What exactly are you doing to "run power through a power probe" (like power from which wire and connecting it to which wire)?



What is the breaker rated at that it's popping?



For the headlight circuit, the power goes from the light switch to the dimmer switch, then 2 separate wires go to the driver side headlight for high beam and low beam. I don't remember which wire is which. From the driver side light, the high and low beam wires jump to the passenger light. I think the headlights are 55w, so there is 5-6+ amps going through the light switch and dimmer switch. If you are trying to use a test light type probe in place of the dimmer switch to make the connection, then it's probably just too much current for the test probe. They are typically designed to be used in parralled where they "see" very little current, not in series where the full current passes through.



A quick test of the low beam circuit would be to use a jumper wire at the dimmer switch to go from the feed wire to the low beam wire. This will bypass the dimmer switch. If you have to redo any of the wiring, I would suggest adding relays and dedicated grounds to the headlights. It's pretty cheap if you do it yourself and the difference is amazing.

A power probe is kind of hard to explain but basically you hook it up to a battery, and you have the option to send positive or negative to a circuit. Here's a link.. when you figure out how to use one really well they are SUPER helpful. https://m.youtube.com/watch?v=GdH-e4Q9p5k

Basically using the power probe on the low beam circuit, I do believe, is the same as using a jumper wire. I did notice too when the low beams start to become intermittent, the dash lights follow. I'm thinking there is a short somewhere in the low beam wire between the dimmer and headlight. Is it a straight shot or does it route to other places?


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[jp360cj]

It's a straight shot between from the dimmer to the headlight.

Does your light switch get very hot? I had a similar issue a while back where my headlights and dash would flicker and/or sometimes not work. Sometimes I could hear it clicking that sounded like a circuit breaker tripping. When it did, the light switch on the dash would get very hot to the touch. It's having to handle the current of all the lights, including the headlights on very small wires. I wired in some relays for headlights and all my light issues went away.

What's the power probe rated for? The 5-6amps I mentioned is only for 1 headlight @55w, so both lights would be double that.

 

[jakeh937]

It's a straight shot between from the dimmer to the headlight.



Does your light switch get very hot? I had a similar issue a while back where my headlights and dash would flicker and/or sometimes not work. Sometimes I could hear it clicking that sounded like a circuit breaker tripping. When it did, the light switch on the dash would get very hot to the touch. It's having to handle the current of all the lights, including the headlights on very small wires. I wired in some relays for headlights and all my light issues went away.



What's the power probe rated for? The 5-6amps I mentioned is only for 1 headlight @55w, so both lights would be double that.

The switch itself does get warm on lowbeams and so does the wiring to the dimmer switch. And as far as the power probe I'm not to sure I'd have to look.


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[jakeh937]

Does anyone have a picture of their headlight switch I can use for a reference to wire placement? And also as far as stock headlights.. what are you guys running? I have 2 different brand lights and I'm wondering if that's causing the issue.. thanks


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[jakeh937]

Finally figured it out in case anyone runs into this issue in the future. The PO wired in the new radio.. cool right? Well somehow one of the radio wires he connected to the high beam indicator for the dash. However, at the dimmer switch itself, I do believe the high beam indicator wire is on the low beam side (hence why high beams worked and lows didn't) I cut the wire at the connection and boom, lights work both high and low. Radio still works. Have no idea what that wire went to for the radio but hey, it plays music and keeps presets * thanks all for the help.


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