Tundra Trailer Running Lights Not Working. Trailer works fine with other vehicle so problem definitely with truck. In the case of the Tundra, the circuitry utilized in the converter was inadequate to properly manage vehicle and/or trailer-side voltage spikes.
I pulled the lid on the fuse box and it seems confusing to me. Brake and signal lights work but running lights do not. (trailer is not the problem). However I have no running lights.
The signals work but I've got no brake lights or daytime running lights.
The fuse for the trailer running lights is behind the relay box on the right side of the engine compartment.
Same story on two separate trailers. The running light pin should always be on, and the brakes and flashers only when activated, correct? Turn signals, brakes, backups work fine.