How to Diagnose the Right Brake Light on Trailer Not Working Properly

Question:

I have a 2004 Chevy Silverado. The right blinker works but not the brake light. Ive tested the trailer on another truck and the right brake light works. Is the RH blinker and brake light powered separately on the truck connector? I believe I have a standard round 7 blade connector installed by the Chevy dealer on the truck. The connector on the truck doesnt have corrosion. The RH brake light works intermittently. I havent tested with a circuit test yet.

asked by: Stuart J

Expert Reply:

As the brake light worked when used on another vehicle, it is definitely something on the vehicle end. I would definitely use a tester, like the # PTW2993, to check the right brake port (3 o'clock position). It would also be advisable to check the wire in the back of the 7 Way to make sure it is not coming loose or starting to break.

One other thing you will want to check is the fuse that handles this function. This will be the RT TRLR (red box) in the panel on the left side of the dash (pictures included). If this fuse is bad, or going bad, it will cause you to not get the power needed.

expert reply by: Lazer S