Procedure for Installation of an Aftermarket Trailer Brake Controller in Lieu of Factory Installed Integrated Trailer Brake Controller

This bulletin is being revised to clarify on which vehicles connector X126 is found. Please discard Corporate Bulletin Number 07-08-45-001A (Section 08 -- Body & Accessories).

Some customers may request to have an aftermarket trailer brake controller added, in lieu of the factory Integrated Trailer Brake Controller (ITBC) RPO JL1. This request may be made if the trailer being towed is equipped with electric over hydraulic brakes. This style of trailer brake system is not supported by the ITBC. An aftermarket trailer brake controller may be installed to operate with the electric over hydraulic brakes, however the factory installed ITBC system will be disabled.

To install an aftermarket trailer brake controller, use the four blunt cut wires located near the data link connector. Make the following changes to the vehicle harness:

1. The Red/Black wire, circuit 242, must be connected to stud #2 of the 30 Amp fuse of the Underhood Fuse Block. This wire is located between the left fender and the Underhood Fuse Block.
2. Locate connector X126 (on vehicles without RPO JL4 ) or X115 (on vehicles with JL4) near the Underhood Fuse Block (Refer to SI Document ID# 1849049). Circuit 47 from the blunt cut wires near the data link connector will end at connector X126 terminal "G" or X115 terminal "B5." Obtain enough Dark Blue 12 gauge wire to run from X126/X115 to the 7-way trailer connector at the bumper. On one end of the Dark Blue wire attach terminal part number 15304732, located in Delphi Tray 8 and insert into X126 "G" or terminal part number 15304720 located in Delphi Tray 19 and insert into X115 "B5." 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 and insert it into the 7-way trailer connector terminal "C".

Important: This procedure will not result in any Trailer Brake related display messages to be set. However, ITBC diagnostics will continue to function. If an ITBC fault is detected, a "Service Trailer Brake System" message will be displayed on the Driver Information Center (DIC) and an appropriate DTC will be stored in the ITBC module. The operator will still be able to adjust gain and access the "Trailer Gain / Output" display page in the DIC. However, the factory installed ITBC system will not sense a trailer connection and will not provide output to the trailer.

This installation procedure is to be performed at the customer's request and at their expense. It is not a warranty repair and a claim should not be submitted for reimbursement.