Troubleshooting a Weak Right Turn Signal on a Trailer Towed by a 2010 Toyota Tacoma

Question:

Installed 4 way tow harness #118496 on a 2010 Tacoma pickup.The left side trailer lights work but the right side has only a weak signal to the turn light but no signal or light when brakes are applied or vehicle headlights turned on. There is a new harness installed on the trailer as well. I could find no problem with the trailer wiring and suspect there maybe something wrong with the vehicle harness. I did check all connections. Could this be a problem with a ground.

asked by: Phil

Expert Reply:

What you described sounds exactly like a ground problem. Pretty much anytime there is bizarre tail light behavior its a ground issue somewhere. I would check the ground of the right light assembly to see if there is any obvious issues that need to be fixed like corrosion, or broken, loose wires.

Chances are it is not the vehicle side of the trailer harness, but you could get a circuit tester like our # PTW2993 and test the circuits individually to rule them out. I attached a video on how to do this for you to check out also.

I attached an FAQ on trailer wiring for you to check out also.

expert reply by: Jameson C