Any Chevy/GMC techs here?

loosenut

Club Member
Having a problem with my 16 Sierra. Dealer isn't really able to help. I have some questions.

Thanks,

Andy
 
Not a tech but if its electronic I'm probably a better bet ;) whats up?

I having a problem with an external trailer brake controller. The truck came with the harness to plug into the block at the bulkhead. Its 4 wires. Power, ground, brake input and output. When I plug in the controller with the trailer attached its not recognizing that the trailer is connected. I get power and ground to the controller. I have power out to the blue wire (brake output). When I go to the 7 pin harness at the bumper, (factory installed) there is no power there. Lights and signals work. I put power to the trailer and the brakes work fine.

We pulled the plug at the bumper and there is a blue wire there. Gets no power from brake controller. Dealer is telling me that their bulletin says that they need to pull the blue wire out of the 7 pin harness and run a new wire from the BCM to the bumper (at my cost of course).

Why would they include a harness to hookup an external brake controller, have a fuse for it, have instructions on how to hook it up in the manual and not have it work? Dealer was baffled. Tech had no idea how to get it working.
 
These are a nightmare on those I've heard, most folks say try to get/buy with the built in.. Chris can help I'm sure, Moneypit may be able to help also.
 
darn gimme some time, My nerds arent that fast, I have a test box we can hook up to check it, any possibility of bringing truck to wixom
 
I have a 15 with the factory controller. My daughter pulled the history on it and it was brought back to the dealer 3 times for a 'Brake Controller' issue...Must be a common problem...

Gary
 
Common issue unfortunately let me see what I can dig up. Worst case if there is an unused wire running back there at the bcm I can just build some software to move it to that pin so you don't have to go through all of thag
 
Common issue unfortunately let me see what I can dig up. Worst case if there is an unused wire running back there at the bcm I can just build some software to move it to that pin so you don't have to go through all of thag

Cool, thanks. Let me know.
 
Does the BCM have to have the option enabled to recognize the difference in load for the auxiliary system or is it a poorly shielded comm/data wire being interrupted?
 
Does the BCM have to have the option enabled to recognize the difference in load for the auxiliary system or is it a poorly shielded comm/data wire being interrupted?

The truck comes with a plug and play harness. It plugs into the bulkhead. It connects to the brake controller and its supposed to work.
 
The truck comes with a plug and play harness. It plugs into the bulkhead. It connects to the brake controller and its supposed to work.

Was just curious since in the past, such features have been known to not function until the module is "told" it's been installed.
 
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