I hooked my 06 duramax up to my trailer. The right brake and turn signal won't work but the running light does. So I thought the bulb was burnt out on thetrailer. I tested it and it wasn't. So then I thought the trailer had a wiring problem. So I plug my 01 truck into it and the right brake and signal worked fine. So I know the problem is in the duramax truck. So I checked the fuze for the right trailer signal and it wasn't burnt out. Then I tested the plug-in and it wouldn't work there. So it is somewhere from the fuze box to the plug-in. Does anyone know where else to look or has anyone else had that problem?

 

I had this same problem on my 05 & If I remember their are 2 fuses 1 under the hood & 1 by the drivers side door. I hope this helps you.

 

ok i will check that

 

ok i went back out and read the manual and everything and i couldn't figure it out. I used my test light on the right trailer signal/brake one and it didn't work. So I tried replacing it and the new one didn't work and the old one didn't look blown. I took the new one out and stuck the test light down in there and nothing. So what could be the problem then?

 

I still think you are missing a fuse like I did!