Trailer Running Lights Do Not Work but Brake Lights and Turn Signals Do Work
Question:
Blinkers and break lights work but tail/running lights dont. Truck tail lights are working. Is it a fuse or is it wiring?
asked by: Joan C
Expert Reply:
It could be a tow package fuse on the vehicle. Use the owners manual to find the locations of fuses/relays related to the tow package wiring to check them and replace as needed.
If the issue is not a fuse or relay then you can test the vehicle side trailer connector using a circuit tester such as # PTW2993. Turn the vehicle headlights on and use the circuit tester to test the pins on the connector at the back. If there is no power on the running light pin then there is a break or loose connection somewhere between the connector and where it terminates at the front of the vehicle that you will need to track down.
If everything checks out on the vehicle then the issue is on the trailer. Make sure the trailer connector is clean and free of corrosion inside and out. The main trailer connector ground and the grounds for all of the lights need to be attached to clean and corrosion free bare metal surfaces.
If there is anything between a light ground and the metal trailer frame or if the trailer has an aluminum frame, tilt bed, or folding tongue, any of these things can interrupt the ground. Running jumper wires from the light grounds to the main trailer connector ground can help.
Anthony A.
4/14/2024
I have brake, turn signals and backup lights in my trailer just no running lights. The fuse is good on the truck and I nothing wrong with the plug. What else could I check?
David A.
1/10/2021
Hello I have a trailer where the running lights don’t turn on but they flash when I lock my truck I’ve tested fuses checked the plug connections any ideas?
Kirby P.
9/8/2020
I a skeeter trailer, and the turn signals, break lights, back-up lights work, but the running lights stopped working. where should i start first looking for the problem?
Will D.
9/8/2020
Was rewiring my trailer last night and everything was working perfectly. I was wiring the trailer hot as I had the truck on and trailer connected as I was doing the wiring. On the last light I let the positive touch the trailer and I heard a sizzling noise and ban my running lights stopped working. I checked the truck for any blown fuses and nothing. My blinkers work and brake lights. I checked the trailer connection at the truck and my running lights are not working. Could I have messed up the harness?
Products Referenced in This Question
Product Page this Question was Asked From
Pollak Metal 7-Pole, RV-Style Trailer Socket - Vehicle End
- Trailer Wiring
- Trailer Connectors
- Vehicle End Connector
- Plug Only
- 7 Round - Blade
- Pollak
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Calvin
5/6/2024
I do not have running lights when connected to tow vehicle, I have jumped the 7 pin connector on camper, the running lights turn on, I checked the 7 pin on tow vehicle and that checks 12 volts, but no running lights when attached to tow vehicle, There's 2 auto reset circuit breakers attached to trailer frame by the battery. What is there purpose and how can i check them???