Disable OEM integrated trailer brake controller

GMequalsPOS · December 3, 2022

Good day,

Every time I start my 2017 Sierra 1500, I get a msg on the DIC, Service Trailer Brake System. Was too costly (repair shops want $180 just to diagnose the issue) to get the integrated one fixed and an aftermarket controller was only $120.

Despite the aftermarket controller being installed and working fine, I still receive the msg on the DIC.

How can I disable/remove/disconnect/stop that f'n msg on the DIC, about the brake controller. I'm hoping there's a way to remove the OEM controller and/or tell the truck it doesn't have a trailer brake system... I've googled to no avail.

Thanks.

64BAwagon · December 3, 2022

You might try disconnecting the wiring at the 7 way plug on the rear of the truck. Sometimes the error is due to corrosion in that plug. It wont cost anything and its relatively simple. I would put something over the connector afterwards to keep debris out of it.

newdude · December 3, 2022

9 hours ago, GMequalsPOS said:

Good day,

Every time I start my 2017 Sierra 1500, I get a msg on the DIC, Service Trailer Brake System. Was too costly (repair shops want $180 just to diagnose the issue) to get the integrated one fixed and an aftermarket controller was only $120.

Despite the aftermarket controller being installed and working fine, I still receive the msg on the DIC.

How can I disable/remove/disconnect/stop that f'n msg on the DIC, about the brake controller. I'm hoping there's a way to remove the OEM controller and/or tell the truck it doesn't have a trailer brake system... I've googled to no avail.

Thanks.

The switch in the dash is probably bad. Most common part we replace for the integrated trailer brake system. p/n 84108373 retails for $76.

If you are set on bypassing, here's what you need to do below:

PIT5282F: Procedure for Installation of an Aftermarket Trailer Brake Controller or In Lieu of Factory Trailer Brake Controller - (Dec 19, 2019)

4. Perform this step ONLY if equipped with RPO JL1 where the customer is requesting the factory trailer brake system be bypassed to add an aftermarket trailer brake controller. Locate connector X185 Or X138 (varies with vehicle build; refer to SI), which is near the underhood fuse block, terminal 32. Circuit 47 ends at the body harness side of X185 or X138 terminal 32, which comes from the X61A junction block. Obtain enough Dark Blue 12 gauge wire to run from X185 or X138 to the 7-way trailer connector at the bumper. Attach terminated lead part number 13327155 to one end of the Dark Blue and insert into the chassis harness side of the X185 or X138 connector terminal 32. Run the Dark Blue wire in its own conduit along the frame to the 7-way trailer connector at the bumper. Remove circuit 47 from the 7-way trailer connector terminal “C” and tape the bare terminal and attach to the harness. Attach terminal part number 12110853, located in Delphi Tray 4, to the other end of the Dark Blue wire, with the correct weather pack seal, and insert it into the 7-way trailer connector terminal “C.”

GMequalsPOS · December 4, 2022

12 hours ago, newdude said:

The switch in the dash is probably bad. Most common part we replace for the integrated trailer brake system. p/n 84108373 retails for $76.

If you are set on bypassing, here's what you need to do below:

PIT5282F: Procedure for Installation of an Aftermarket Trailer Brake Controller or In Lieu of Factory Trailer Brake Controller - (Dec 19, 2019)

4. Perform this step ONLY if equipped with RPO JL1 where the customer is requesting the factory trailer brake system be bypassed to add an aftermarket trailer brake controller. Locate connector X185 Or X138 (varies with vehicle build; refer to SI), which is near the underhood fuse block, terminal 32. Circuit 47 ends at the body harness side of X185 or X138 terminal 32, which comes from the X61A junction block. Obtain enough Dark Blue 12 gauge wire to run from X185 or X138 to the 7-way trailer connector at the bumper. Attach terminated lead part number 13327155 to one end of the Dark Blue and insert into the chassis harness side of the X185 or X138 connector terminal 32. Run the Dark Blue wire in its own conduit along the frame to the 7-way trailer connector at the bumper. Remove circuit 47 from the 7-way trailer connector terminal “C” and tape the bare terminal and attach to the harness. Attach terminal part number 12110853, located in Delphi Tray 4, to the other end of the Dark Blue wire, with the correct weather pack seal, and insert it into the 7-way trailer connector terminal “C.”

Thank you for that. Although I didn't mention it as it wasn't related to my original question, I did try replacing the dash switches. Didn't resolve the issue, also checked the connectors at the rear of the truck, reseated everything, checked for voltage at the controller by the spare tire, etc. Anyway, the aftermarket controller is installed and working.

After googling that GM bulletin (thanks again) and that step 4, what it appears to me, is using the truck's existing wiring between the cab and under the hood (instead of having to run your own wire through the firewall) from the aftermarket brake controller to the 7-way trailer connector. As it also indicates that you need to run your own wire from the 7-way connector to that terminal block under the hood.

With that GM bulletin number, I found this (https://www.duramaxforum.com/threads/adding-aftermarket-brake-controller-to-2015.1017203/) post where someone basically did the same thing, following that bulletin (plus some extra) and in one of their pictures, I can see in the DIC, that the truck still knows the ITBC is there.

So although that bulletin explains the easiest way (not really) to install an aftermarket controller, bypassing the truck's blue brake wire, it doesn't actually disable/remote the ITBC, it just doesn't use it to supply the voltage on the 7-way trailer connector. Hope that makes sense.

0216HD · December 13, 2022

2016 2500HD has been telling me to service the trailer brake since new. Dealer attempted many times under warranty but never succeeded. Sometimes it works, sometimes not. Sometimes after connecting a trailer a shut down and restart will bring it online but not always. Notice comes on with every startup with or without a trailer connected. After I gave up with dealer I personally have replaced the circuit board in dash and the module above the spare tire. Resistance tested all the connections I could find and searched for chafed / broken wires. I've had countless conversations with GM. Best they have ever did was offer me a $100 coupon to get my truck serviced at dealership. I'd be interested to hear from anyone with a working background of the problem that might offer some suggestions as to where to look next.