OEM trailer brake controller and wiring

Saldog · March 20, 2015

I want to install a trailer brake controller on my 2014 GMC Sierra 1500 SLT Z71 with the 5.3, it has the 3.42 rear end. I like the looks of the factory brake controller (mine does not have it) and I would like to go that route....do you know if the factory wiring is located behind the panel where I can purchase the necessary controller and dash molding and install a factory brake controller?

I did a search for this topic and did not see this come up anywhere else.

Any info would be helpful.

Thanks,

Saldog

Gmcant33 · March 20, 2015

I think this will be another SLE headlights to slt headlights dilemma but could be wrong but I wouldn't be surprised if it involved lots of $$

tbarn · March 20, 2015

If I understand you correctly, it cannot be done.

Subject: Adding Integrated Trailer Brake Controller RPO JL1

Models: 2014 Chevrolet Silverado 1500 2015 Chevrolet Silverado, Suburban, Tahoe 2014 GMC Sierra 1500 2015 GMC Sierra, Yukon Models

This PI was superseded to update Note section. Please discard PIT5241A.

Some customers may request the factory Integrated Trailer Brake Controller (RPO JL1) be installed on their Full-Size Pickup or SUV when the vehicle was not ordered with the option.

This is to advise you that - if the vehicle does not have the option (RPO JL1), it cannot be added to the vehicle.

Edited March 20, 2015 by tbarn

austingta · March 20, 2015

That is my impression too...it cannot be done.

TJay74 · March 20, 2015

Correct, it is not possible on the K2xx trucks to add the factory trailer brake controller. You can get the harness from GM at no charge that allows you to run an aftermarket controller instead.

Gmcant33 · March 21, 2015

I rest my case.

Saldog · March 22, 2015

Thank you for the prompt reply, I am surprised to hear that.

TJay74 · March 22, 2015

it is because it will require BCM programming that GM no longer allows the dealer to make changes to.

darkfox1 · March 22, 2015

This is the way it was in the GMT-900 too iirc.

The wiring is there though. If you want to work with some aftermarket BCM programming folks to see if they can enable it... but there's no guarantee it's ALL there.

Don't know that GM can no longer re-do the BCM. Just a few weeks ago I spoke to a dealer who said they could reprogram my BCM to accept factory fogs despite there being no RPO for them on my truck.

Note the top harness plugging into the empty pocket where the switch goes.

TJay74 · March 22, 2015

I know you posted that up, but that dealer is smoking it and doesn't know it yet. I am on a really good basis with my dealer, they called the GM place they deal with. GM will not change the programming of any module for your vehicle for any features you add that your truck did not come with from the factory. Back on the GMT900 trucks you could use the VIN from a truck with the option and use that to flash your BCM, cant do that on the K2xx trucks.

When they plug in the laptop to your truck they have to put in your VIN, the system checks to make sure the VIN inputted matches the VIN in the module(s). If they don't it will not go any further in the process. once the module and VNI is verified then they can flash the most recent update for that module for your VIN.

Chris explained it awhile back as to why they do it, I don't remember the full explanation. GM is closing the loop holes with each new generation, before long GM will have it to where you cant even tune the vehicles if they have it their way as will other manufactures.

darkfox1 · March 22, 2015

Well, in the case of the trailer brake controller, you're probably not dealing with something traditional here, so much as you're dealing with an interface into a complicated system. The stock controller probably integrates into existing hooks for wheel speed, brake pedal pressure, speed, etc. So the chances of "going around" a locked out BCM won't work either.

The guy I spoke to at the dealer told me he had called GM "techline." The process he described was to plug the laptop into the truck, get techline into the laptop and they would "take over."

TBH you're probably right, but this is the process I was given, and I honestly didn't believe him, which is why I asked twice. He swore they could do it.

Edited March 22, 2015 by darkfox1

TJay74 · March 23, 2015

it would be great to see that, believe me. only one way to find out is to become a guinea pig and try it though. I went the opposite way, I wanted to remove my brake controller as I don't need it and wont ever use it, I bought the other trim bezel to even get rid of it. I unplugged the controller and as soon as I fire the truck up got a warning of brake controller failure and to see the dealership. Came on at every start up.

I remove the main switch from the trim ring and stuffed it back into the back of the dash out of the way for now.

bwh2003 · March 23, 2015

it would be great to see that, believe me. only one way to find out is to become a guinea pig and try it though. I went the opposite way, I wanted to remove my brake controller as I don't need it and wont ever use it, I bought the other trim bezel to even get rid of it. I unplugged the controller and as soon as I fire the truck up got a warning of brake controller failure and to see the dealership. Came on at every start up.

I remove the main switch from the trim ring and stuffed it back into the back of the dash out of the way for now.

You really find the small cubby hole of the other trim bezel useful enough to remove the trailer brake controller? I actually had to re-read your post because I cannot understand a situation where removing the controller would make sense.

TJay74 · March 23, 2015

Yep, for me it was. I have/had absolutely 0 need, want or desire for the controller on my truck. I had no other option though as the dealership I got my truck from ordered all of their trucks with them no matter what. So unless I wanted to place a custom order and wait 8-10 weeks at the time then I was stuck with it. I will never tow anything that has a braking system on it, I use the truck to drive back and forth to work and make sure I can get here in any weather since I am an essential employee to keeping the electricity on for people.

The most that ever goes in the bed is our bicycles for races or stuff we need for the house, sometimes we use the receiver hitch bike carrier as well.

When I bought the other bezel I thought the cubby would be bigger, so yeah it doesn't get much use but I like it better for some reason than having the controller sitting there instead.

darkfox1 · March 23, 2015

Sure would be useful to have..

I wish my truck came with it.. (and the 3.42s to actually pull something...)

Sadly.. the random used truck on the lot didn't.

This bcm lockdown thing kinda burns my bacon a little bit. If I wanna put GM parts on my GM truck and have GM install the accessories, what's the problem? Why be a jerk about it? I mean I'm spending my money elsewhere here.. it's not like someone other than a billionare's gonna go "WHELP, time to trade the truck since it doesn't have a brake controller!" GM is LOSING MONEY with this approach.