Low Voltage on Brake Output of Factory Brake Controller on a 2008 GMC Sierra 2500HD

Updated 05/13/2019 | Published 05/10/2019

Question:

Hello I am only getting 1.5 volts on my electric trailer break prong on the seven prof plug on the back of my truck and it’s not enough to get the trailer breaks to work. I have check my grounds by running a wire from negative battery terminal clear to back and bypass the grounds between the battery and the back of the truck and still getting low voltage. I think my break controls system relay is bad because it keeps coming up on the bash. Would that be causing my voltage problem as well ?

asked by: Dalton H

Expert Reply:

I would love to help but it sounds like you have a factory integrated brake controller (ITBC) on your 2008 GMC Sierra 2500HD and if that is the case then you would need to take the vehicle to a service center as this is not something we can really offer advice on. If you have an error message then that would explain the low voltage on the brake output wire.

However, this might be a good time to upgrade which I can almost guarantee will be more cost effective than most likely even the diagnostic procedure for your factory integrated brake controller (ITBC), let alone the actual repair bill. For this, I recommend the Tekonsha Primus IQ Trailer Brake Controller part # TK90160 which is a very good option that will outperform your factory integrated brake controller (ITBC) tenfold. In order to install this brake controller bypassing the factory integrated brake controller (ITBC), you will need to follow the instructions in the attached article.

expert reply by: Conner L