Running Lights on Trailer Not Working, Vehicle 7-Way Tests Good

Question:

Running lights on my bumper pull camper do not work. I have 11.5 volts from truck to my 7 pin connector from ground pin to running lights pin, but when connect to trailer no lights. Blinkers and brakes work. I grabbed an extra battery and ran wires straight to the neg pin and pos pin to running lights on camper and they work. Is it a bad ground? Replaced both male and female 7 pin connectors already.

asked by: Tyler

Expert Reply:

There is a possibility that the ground for the tail lights on your trailer is not sufficient for the running light circuit so I would start here as it is rather easy to do. However, if both sides of the trailer are not working and the other lights (stop/turn) are working then that leads me to believe you have a shorted wire. I recommend obtaining a circuit tester and testing the brown wire just behind the trailer side trailer connector while the running light circuit is active. If you don't get power here then the wire leading into the back of the trailer side trailer connector might not be secure. If you don't get power here then you need to trace this wire back to each tail light assembly. The other option you have is to run a new wire entirely with part # 16-1-1 (per foot).

expert reply by: Conner L