Intermittent exterior lights and gauge cluster problems

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GR4

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Joined
Sep 7, 2024
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Location
North Carolina
My Car
1972 351CJ Mach 1
Hi I have a 72 Mach. The headlights and tail lights, side markers, come on and off intermittently and different intervals at different times, sometimes headlights only sometimes tails and side markers only also the gauge cluster flashes intermittently and randomly all after about 10 minutes of driving time. Thoughts?

I have researched, ground wires, engine strap grounds, and bulbs themselves with no solution.

Also what does this green wire near highbeam switch go to? It’s only about 4inches long off the harness.

Thanks!!
 

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What Midlife said...

If you've upgraded to halogen headlights, you may simply be drawing too much for the headlight circuit breaker to handle. I ended up running a relay harness for my Cibie H4 headlights and no more problems.
 
I also ran into this issue, the battery wire to my headlight switch was getting so hot you couldn't touch it and was causing issues. So I ordered a new switch and relay set and no problems ever since. Good luck!!
 
Hi I have a 72 Mach. The headlights and tail lights, side markers, come on and off intermittently and different intervals at different times, sometimes headlights only sometimes tails and side markers only also the gauge cluster flashes intermittently and randomly all after about 10 minutes of driving time. Thoughts?

I have researched, ground wires, engine strap grounds, and bulbs themselves with no solution.

Also what does this green wire near highbeam switch go to? It’s only about 4inches long off the harness.

Thanks!!
Update: thanks to midlife suggestion, I replaced the headlight switch and a bad side marker socket and headlights and taillights work and stay on! Thanks!

Next Im replacing the voltage regulator on the gauge cluster to see if that fixes its light problem. Also still no reverse lights but not concerned with that at the moment.
 
Unlikely, if you are still talking about exterior light issues.
No exterior lights seem to be fixed by changing the light switch, but the gauge cluster lights still are intermittent or not at all working at at the moment that’s why I was wondering about the circuit board on the back of the gauge cluster is that may help with those lights.
 
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