I have a 2004 Chevy CC/SB Duramax/Allison. My problem is I have no right trailer brake light signal. I have both turn signals, and a left brake, but no right. This would indicate to me that the fuses are good, and the appear that way. I checked the junction under the rear driver side of the bed, but it doesn't appear that the trailer lights originate from there. Is there a relay that combines the brake signals with the turn signals under the hood somewhere that could be bad, or any ideas on where to start looking before I have to take it in to the dealer? Thanks!

there is a fuse for left and right trailer lights IIRC.

I checked that, the fuse is good. I have right trailer turn signal, just no right trailer brake. Which leads me to beleive it is somewhere in the main wiring box under the hood, but I have no idea where to start looking in there.