Installing Aftermarket Trailer Brake Controller

[micwtx]

I'm a new member so please bear with me. I have a 2010 silverado 2500HD with integrated trailer brake controller. The ITBC was damaged while installing a fifth wheel hitch and we need the aftermarket to pull a trailer until the replacement ITBC comes in (may be more than a month).

I have searched for all the posts in the various forums regarding installing an aftermarket trailer brake controller and have read the posts. Several list a publication giving instructions on how to do this and why but it referes to other publications that I cannot find.

My problem is #07-08-45-001D is the procedure for installation but then it tells me to refer to SI document #1849049 - I/P Harness- Engine compartment.

I have been able to get the turn signals working (were always working) and think I just need to get the red wire for the power connected and run the blue wire for the brake signal to trailer connector. I can't find the x126 or x115 terminal mentioned in the instructions.

Can anyone point me in the right direction?

Thanks in advance for the help, and Happy Holidays!!