ITBC Schematic

[Estm8r85]

I have a 2007 Sierra 2500HD (K2500) Duramax. After the 'Service Trailer Brake System' DIC message appeared I changed the Controller and checked both fuses. The message persists. I am not able to find the ITBC on any of the schematics I have and not on the internet, either. Does anyone have one or can you point me to one?

[riverbanks]

Did you check and clean connections on relay by spare tire?

[Estm8r85]

I replaced the controller and oiled the connecter. Mine is on the frame rail.

[swathdiver]

This is from my year.  You may have some pinched or corroded wiring somewhere.