I drove the truck last sunday to move it to the driveway, I saw the "service trailer brake" msg on the dash.
I did some research, looks like it is a TSB,

Could you please what was the correction/fix done to fix this, my chevy dealership in Grand Rapids, MI is quick to jump to conclusion or blow stuff away as working as designed...

Thanks

If you didn't have a trailer connected, one of three things has occured.

Moisture (water) in the bumper mounted socket is creating a circuit from blue to black (brake to ground) at a high impedence.
The relay mounted by the brains in the rear is goin' south
If you truck has the 5th wheel wiring provisions, the blunt cut wires on the driver's frame rail have allowed a high impedence connection of the blue to black wire (again from moisture)


Check the glove box code sticker for "UY2" (5th wheel wiring provision). If you have it, the description of it's location is here http://www.dieselplace.com/forum/showpost.php?p=3023917&postcount=4

The relay mounted by the brains in the rear is goin' south
/forum/showpost.php?p=3023917&postcount=4 (http://www.dieselplace.com/forum/showpost.php?p=3023917&postcount=4)


Are you referring to the Trailer Brake Control Module (TBCM)?

Are you referring to the Trailer Brake Control Module (TBCM)?
Yes.......AND I forgot about the updated calibration available here http://www.dieselplace.com/forum/showpost.php?p=3890100&postcount=15

OH, I see that there are two items under there, the TCBM and also a relay. The diagnostic says if all other conditions don't produce the fault condition, replace the relay.