Integrated Trailer Brake

[JohnnyR]

2012 K3500 Duraamax. This message popped up today from the DIC: Service Trailer Brake system. That indicates a fault in the integrated brake controller system. I was not towing anything when it occurred. So I checked the controller fuse beneath hood and it was OK. Then checked the connections from truck electrical system to the 5th whl plug, meaning i diconnected them and plugged them together again. Still getting the message. Anyone run into this before?

[CoyleJR]

There is a separate fuse for the third brake light on the roof on my 2006. That fuse also controls the electric brake circuit and could cause the code on your 2012. It is an easy check, just look and see if the 3rd brake light is working.

Good luck
John

[DmaxMaverick]

There is a separate fuse for the third brake light on the roof on my 2006. That fuse also controls the electric brake circuit and could cause the code on your 2012. It is an easy check, just look and see if the 3rd brake light is working.

Good luck
John

That fuse may be labelled "CHMSL".

[JohnnyR]

Thx guys. I'll check later this afternoon.

[JohnnyR]

Checked all the fuses and found the 15 amp fuse for trailer backup lights was burned out. Replaced it but that did not fix problem. Still getting the Service Trailer Brake System message. BTW, rear cab brakelight was working. Thought I had found the problem with other blown fuse but apparently not. Owners manual suggests cutting ignition off and restarting is enough to reset system. Should I disconnect batteries to reset everything?

[JohnnyR]

Dealer replaced the master cylinder brake pressure sensor.