sack1

You guys are the best. My '03 2500HD worked fine on the truck but the RR brake light on the trailer plus the pin out on both 7-way receptacles were dead for that brake light, everything else worked fine. In our case I knew it was intermittent since my wife would occasionally mention it when guiding me back So on the hunch taken from this thread I took the dash fascia off and located the module. Little hard to get it out but with some wiggling it came forth. I noticed too that the cover of the module came off easily and inside is a logic board and open relays. So I replaced it in the socket, by the way, truck lights did not all work with the module out, I tapped on the module cover with a screwdriver and what do you know, the beast inside awakened! It worked! I still plan to buy a new module, NAPA's is as cheap as anybodies, but perhaps this might be an easy test to see if the module, and probably a relay, is sticking. Give it a few raps on its cover. Thanks again for all the troubleshooting. -Rick