How to locate a damaged wire in a car?

[rawhide]

I have a 2015 Jeep Patriot that has been driven very little over the past 20 months and parked in an insulated shop. The right tail lights are not working and the wiring is not easy to access. I’m not a great mechanic, but with guidance and YouTube I can usually figure things out.

Can some of you gearheads tell me how to go about isolating the problem? I have wire testers and a cheap voltmeter.

 

[Okie4570]

If you haven't started with a test light, start there first. The entire plug crapped out on the rear driver's side of my daughter's jeep a few years ago.

 

[OKRuss]

Does the turn indicator light flash rapidly on the dash, look like normal blinking or nothing?

 

[Prairie Wings]

Check for blown fuse.

 

[SoonerP226]

A test light isn’t always a good option because some wires in a modern car’s wiring harness are carrying lower signal voltage rather than the normal 12V line voltage, so shorting them to 12V ground with a test light can damage the electronics connected to them. That’s probably not the case with wires going to lighting, but it bears mentioning.

If you have a multimeter and a roll of 12ga or 14ga automotive wire, it’s easy enough to ohm out a wire if you can find the connectors at either end of it. Just use the roll of wire to make a jumper to reach the far end of the wire and set your meter to ohms, then check for continuity. It won’t tell you where the break is, but it’ll at least tell you which wire is broken.

 

[Okie4570]

A test light isn’t always a good option because some wires in a modern car’s wiring harness are carrying lower signal voltage rather than the normal 12V line voltage, so shorting them to 12V ground with a test light can damage the electronics connected to them. That’s probably not the case with wires going to lighting, but it bears mentioning.

If you have a multimeter and a roll of 12ga or 14ga automotive wire, it’s easy enough to ohm out a wire if you can find the connectors at either end of it. Just use the roll of wire to make a jumper to reach the far end of the wire and set your meter to ohms, then check for continuity. It won’t tell you where the break is, but it’ll at least tell you which wire is broken.

It's a jeep liberty

 

[chuter]

Do you have a wiring diagram? Might be able to find one online.