Power is Getting to the Trailer Lights But they Will Not Light Up

Published 11/01/2013

Question:

I can not get the lights to lite all have power and lite the tester but not the lights on the trailer, I cleaned ground area on trailer inside is a plug into the wiring system

asked by: John

Expert Reply:

Use your circuit tester to test the wiring directly at the back of the lights. If the power is not getting to that point then there is a wiring issue that you will need to track down and repair. If power is getting to the light and the light is not coming on then the issue is either a weak or bad ground or there is something wrong with the light.

The ground needs to be attached to a clean and corrosion free bare metal surface. Try moving the ground to a different location or run a jumper from the ground location to the main trailer connector ground.

To test the light itself you can disconnect it from the trailer and attach the wires to a separate battery to see if the light lights up. If it does not then there is either a problem with the light wiring or the bulb is burned out.

On some trailers, if you have a lot of clearance lights, that can sometimes overload the tow package wiring on the vehicle and some or all of the lights will not work. If each light works individually then this could be the issue as well.

expert reply by: Michael H