Troubleshooting Trailer Lights Not Working WIth 2003 Jeep Liberty  

Question:

Expert Reply:

It is pretty unlikely a module is bad for a wiring harness, so you'll need to troubleshoot, and I can give you some things to check out. You mentioned you have power, but you'll also want to take a look at your owner's manual to locate any trailer fuses or relays and ensure they are all there and in working order. If they are, in order to determine the specific problem you will need to use a circuit tester like # PTW2979 and test the connector on your vehicle after disconnecting it from your trailer. Check the wiring going into your harness from your tail lights to see if those wires are carrying the correct signals, if not then the issue is with the vehicle wiring.

If the signals going to your harness are okay, you'll need to test the signals coming out of the harness, and if they are correct then your issue is likely going to be with the trailer side wiring. You will also want to check both your vehicle and trailer connectors for corrosion, which can be green or white in color. A build-up of corrosion can interfere with the signals getting through the connectors so if it is present on the trailer side connector you are going to need to replace the plug with # 18004. You'll also need to make sure your grounds are attached to bare metal surfaces and free of any paint, dirt or corrosion.

I have added links to a pair of help articles on trailer wiring, including a troubleshooting guide which I highly recommend taking a look at.

Additionally, I also highly recommend using Dielectric Grease for Electrical Connectors # 11755 to help prevent any type of corrosion in your connector; using it will increase your 4-way's durability and extend its lifespan.

expert reply by: Kyle S

0