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AR15.COM
3/26/2016 10:27:08 PM EDT
I have a 2011 3/4 ton GMC Yukon XL, with GM's integrated trailer brake controller.  Last week, my DIC flashed a message saying "Service Trailer Brake System".  I didn't have a trailer hooked up, so I'm guessing something didn't initialize correctly after I started the truck.  I found the ITBC on the passenger frame rail, and it was covered in mud/cow shit/grass/sticks, so I unplugged everything, cleaned it up and plugged it back in.  I still the the same message on the DIC, but now I can't even adjust the trailer gain (no numbers even display on it).  It seems as though I borked the ITBC module when I cleaned everything up.  

Is this a user-replaceable part, or do I have to take my truck to the dealer for reprogramming/module flashing/upgrading or whatever else?  Any GM techs in the house?  Thanks.
3/27/2016 7:54:24 AM EDT
[#1]
Take to the dealer or a shop that has a Tech 2 scan tool, to see what is wrong, just don't throw a module at the truck, many times doesn't fix it.
3/28/2016 12:32:20 PM EDT
[#2]
Well, I spent the whole weekend looking at wires, tracing them back, checking for breaks/corrosion, and couldn't find a damn thing.  Truck is at the dealer this morning.  I can't wait to find out what it's going to cost me.  
4/7/2016 12:07:59 PM EDT
[#3]
Quote History
Quoted:
Take to the dealer or a shop that has a Tech 2 scan tool, to see what is wrong, just don't throw a module at the truck, many times doesn't fix it.
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Turned out to be the ITBC relay.  Glad I didn't buy the ITBC module and try installing that.