Troubleshooting Trailer Taillights Not Functioning on Trailer Where Signal is Present

Updated 04/17/2019 | Published 04/16/2019

Question:

The tail lights on my trailer arent working and Im about to go insane trying to figure things out. The running and break lights work and the turn signal work properly. The tail light, lights up on my tester while plugged into my vehicle. Each tail and running light is grounded independently using the white wire and attaching it the the metal frame. With each ground, I sanded down to bare metal to connect the white wire. The trailer connectors white ground wire is also grounded to the trailer tongue again bare metal. I will also mention that the light to shine on my license plate doesnt work either. What could be wrong?

asked by: Dennis B

Expert Reply:

Sounds like you most likely are drawing too much power on the running light circuit and all of the lights aren't able to light up. Normally this might blow a fuse but in some cases it just won't power the lights. If it's not the amperage capacity of the circuit it can also be too thin of wire used and the wiring just can't handle the amperage. One way to test this is to unplug or disconnect most of the running lights to see if at any point the circuit will light up the remaining ones plugged in. If this is the case then it's too much amperage draw or too thin of wire.

Easiest solution though is to go to LED taillights as they require far less amperage. I attached a link to a page that has all of the LED trailer taillights we offer as well.

expert reply by: Jameson C