2001 2500HD Trailer No Right Brake Light

highroller152 · May 27, 2015

Hi all,

So my 2500HD stopped sending my trailers the right (passenger) brake signal. I have right turn but no right brake. Multiple posts are talking about a flasher relay - so I replaced mine (GM 12450072) with no change. It's a smaller flasher unit than what most of the posts are talking about (4-pin, not 10). I don't have the 10-pin relay. Is there another converter box that I'm missing? I've pulled, cleaned and tested all the fuses in both the fuse blocks and no love.

Does anyone have any ideas? Thanks for the help folks.

davester · May 28, 2015

So, you've checked the plug on the truck and it's not producing the signal? I'd first check the connections around there [at the plug, and maybe if there is a harness connector for it].

Ianf · May 28, 2015

If the left brake on the trailer is working then the problem is not in the truck but with the trailer itself. They use the same feed wire off the hitch connector. Therefore the problem has to be from that connector back to the light.

highroller152 · May 28, 2015

I have two 7-pin plugs - both factory installed. One next to the bumper hitch under the tailgate and the other in the bed of the truck for a cab-over-camper/gooseneck. There is no voltage to the right brake wire from under the cab of the truck (in front of either plug). The turn and brake signals for each respective side come across the same wire (so left brake&turn and right brake&turn). When I hit the right turn, I get correct voltage. When I hit the brakes, nothing on the right.