Why Would Turn Circuits on Trailer Function but Not Stop Circuit

Question:

On my 2011 tocoma I have a 4 pin connector conning from the truck to the trailer left and right turn signal working running light working but no brake light

asked by: Andy

Expert Reply:

So trailer wiring carries the stop and turn circuits on the same wire which makes wiring in a dedicated stop light more involved. To do this you have to have a signal converter to take the signal from combined to separate.

What you'd need for this is a converter like part # 118158. Most likely your trailer does not have one of these or the one it has is damaged. Trace the wiring of the brake light till you find a converter (if present). Otherwise you can install this converter and be set.

expert reply by: Jameson C