Trailer Lights, Driver-Side Running and Parking Light Not Working on 2015 Jeep Wrangler

Question:

Connected my utility trailer, that had original 4 pole flat connector wiring, to my tow vehicle. Tow vehicle is also 4 pole flat connector original wiring. DRIVERS side RUNNING LIGHT and drivers side FRONT PARKING LIGHT did not work. NONE of the lights on the TRAILER worked. However, DRIVERS side BRAKE light, BACKUP light, 4 way FLASHER, REAR TURN signal and FRONT TURN signal all worked with the trailer connected to my tow vehicle. All other lights on my tow vehicle functioned properly with the trailer connected. Disconnected trailer, found and replaced 15 amp mini fuse that had blown. All tow vehicle lights now working. Rewired trailer with new wiring kit. Connected rewired trailer to my tow vehicle. SAME PROBLEM. No trailer lights, no drivers side running light or parking light and blown 15 amp mini fuse. But again, all other lights on the tow vehicle functioned properly with the trailer connected. Disconnected trailer and again replaced blown 15 amp mini fuse. Now all tow vehicle lights are working properly and no blown fuses. But I cannot use my utility without proper working lights. Help.

asked by: Ron

Expert Reply:

Since you are able to get all of your vehicle lights working without the trailer connected, the issue is likely on the trailer wiring. First, check your trailer wiring ground connection for signs of a bad connection. Clean the area around your ground connection to get rid of any paint, corrosion, or other buildup. Make sure the ground wire is securely connected to bare metal on your trailer frame.

Next check your trailer 4-way connector for any signs of corrosion on both inside and out, although this is unlikely since you said you rewired your trailer with a new wiring kit.

If these steps still don't fix your issue, check the connections on your vehicle wiring harness. You can use a circuit tester such as # PTW2992 to verify the functions on your 4-way connector to ensure they are wired in the right spot. Then, check your wiring for any signs of damage (exposed wiring, pinched wires, loose connections) and replace any damaged wires.

I have attached our 4-way troubleshooting guide below for you to reference as you work through these steps.

expert reply by: John R