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.
Doug M.
7/11/2020
On my 2018 Ram 1500 crew Ref: my boat trailer All my truck lights work but on the boat trailer only the driver side running light and blinker work, nothing works on passenger side trailer (and the boat and trailer are only one month old)
Chris R.
7/16/2020
Angie
8/2/2020
Hello, I have a 2020 Honda CRV. I had Uhaul install a hitch. The trailer we are pulling worked great until we launched waverunner. Now all lights stay on , even when car is turned off. Blinkers and brake lights on trailer do not work. Uhaul replaced plug in play after first time this happened . First time I launched after repair it did it again. Any suggestions?
Jon G.
8/11/2020
Philipp
9/6/2020
I have a 2015 Dodge Grand Caravan that I had the dealership i bought it from brand new,install a mopar factory trailer wiring harness on. Left and right signals work and brake lights but No Running Lights. I checked owners manual for fuse location and there are no fuses in there. I think when they installed it, they spliced all the connections. I couldn't find any in-line fuses either
Jon G.
9/8/2020
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?
Jon G.
9/8/2020
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
more information >
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Scott
5/19/2020
Hi there. Having a strange issue with my trailer lights. Brake and turn singles work but not my running lights within the brake, turn and running bulb. All other running lights work around the trailer. What’s weird is I have 12.4 volts going to all pins on the plug and yet the running lights still don’t work? The light itself is a single bulb light so not a blown bulb. Any ideas would be greatly appreciated. Thanks so much.