I accidentally posted this in the mod forum, but hopefully this can help...

I recently acquired this cherokee with an abundance of issues. One of the main ones being that the tails lights are out - turn signals, brakes and headlights work fine.

I replaced the lights, fuses and even the switch in the dash, but to no avail. The previous owner put in a bunch of foam insulation in the body of the vehicle and I'm not sure if that is inhibiting the wires somewhere.

Is there a way to fix or diagnose this issue without taking it to get rewired?

 

is it liquid expansion foam? i doubt that this would mess with the wires. if the foam pushed the wires into anything, the wires would just sink into foam and probably not actually touch or rub something to damage them... however, jeeps are notorious for weak/faulty wiring. so i guess the possibility of the wires being stretched enough to disconnect or something is possible... cant totally rule it out... other than that, checking the wires anywhere they fit thru a gromit or where there is a connection is a good place to look. behind the dash are the relays for the switch, could be there. this is one of those odd issues that might be a simple fix, but requires some troubleshooting to get there. GL!

 

Yeah, it's the liquid expansion stuff. It's really irking me because I can't drive at night without the tail lights. I guess I just have to take a couple hours and really troubleshoot this headache.

 

I'm not too thrilled about going into the body of the vehicle and scraping out all the foam, but it might just have to happen.

I did a test light on the tail light encasement and of course I don't have power back there. Could it be possible that it is a circuit breaker? The guy at autozone claims that it relays from the blinker encasement and could be a blown wire there, but that seems a little far fetched for me.