Anybody got any reasonably good ideas/sources on how to troubleshoot an intermittent issue where the rear running lights (and license plate light) don’t light up while the headlights are turned on during times of day when it is cool/cold and damp? Which, coincidently is when it is dark outside making this issue very inconvienient.
Breaklights work, blinkers work, hazards work. Bulbs are okay.
Checked all the fuses and replaced the headlight control switch. Things worked yesterday afternoon when it was sunny and hot but not today in the early AM while its cool and damp.
I’ve never “tested the grounding” and haven’t had the time to skim through every “how to” video to weed out all the ones that just say to check fuses/bulbs and then take it to a mechanic.
One of the rear light covers is cracked. Would there be a chance that condensation in there would be enough to short out the running light circuit but not all the other light circuits?
Had a quick google before I crawled out of bed to get ready for work, but couldn’t find much. Here’s a similar sounding issue
I’d pull out a voltmeter and check what’s going on at the pins for the lights.
Here’s a link I found to the service manual in case that helps: https://www.dropbox.com/scl/fo/y2xpmlxsqeu6pnog3lie6/h?rlkey=213q0rnrpk3cdebmg81afa6v1&dl=0
Edit: also found this, do you have dash cluster/marker lights working? If not it might be the switch, which should be cheap to replace and a lot less annoying than tracing wires to find a short lol. see post #12 for how to check the switch https://www.wranglerforum.com/threads/no-dash-lights-or-park-lights-on-tj.2413629/
No cluster lights but that has been an issue for longer than the running lights not consistently working.
Replaced the switch with a new one, so I can confidently rule out a faulty switch.
ugg… its going to be something like a melted plug or cracked wire somewhere…
My bets on cracked or rubbed through wire, hopefully it’s not too buried since it’s a Jeep? I’ve given up before and also just run a new wire along the original wiring harness, but don’t love doing that because if one wire is junk, that area is probably gonna cause issues in the other wires eventually.