Adding GM factory trailer brake controller

[DrNick]

On 7/27/2020 at 11:01 AM, rallysport096 said:

@pgamboa Phil, did you ever get it figured out? Thanks!

In for this.  I know this has got to be a major PITA to develop a solution for, but consider me one of the first in line if it can be made to work.

[truckmann]

I know this is kind of old, but I just added a Redarc to my 2014 and figured I'd share my control mounting location since I've not seen anyone else put it where I did and yes I know my truck is filthy right now. 

 

Edited January 14, 2021 by truckmann
Image Edit

[JonMS]

On 10/23/2020 at 5:19 PM, truckmann said:

I know this is kind of old, but I just added a Redarc to my 2014 and figured I'd share my control mounting location since I've not seen anyone else put it where I did and yes I know my truck is filthy right now. 

 

Can you re-add the picture? I just got my redarc and trying to figure out where I want to put it. Thanks

[truckmann]

32 minutes ago, JonMS said:

Can you re-add the picture? I just got my redarc and trying to figure out where I want to put it. Thanks

I'm assuming you can't see my picture so I just edited my original post to change how the image is attached. Let me know if that works for you. 

[jakey0318]

I have a 2017 Chevy Silverado crew cab LT model and it didn’t come with the trailer brake control module on the dash but I added it and it was a plug-in play and it’s not working. Everything else is working the brake lights do and the blinkers does computer need to be flashed or turned on or I have no idea someone please help. I have checked the harness. It’s in good shape. Everything looks right and all of the fuses are in the right places.

[newdude]

6 hours ago, jakey0318 said:

I have a 2017 Chevy Silverado crew cab LT model and it didn’t come with the trailer brake control module on the dash but I added it and it was a plug-in play and it’s not working. Everything else is working the brake lights do and the blinkers does computer need to be flashed or turned on or I have no idea someone please help. I have checked the harness. It’s in good shape. Everything looks right and all of the fuses are in the right places.

 

 

You...can NOT...add...the...factory GM integrated controller...

 

Here's the defacto no straight from GM - PIT5241E Adding Integrated Trailer Brake Controller RPO JL1 (nhtsa.gov)

 

Take the factory switch out of the dash, sell it and get any brand aftermarket brake controller and install it.  

 

 

Edited April 21, 2024 by newdude

[sk]

What newdude said.

 

If you use the search feature on these forums you will find lots of thread discussing this, but like the bulletin above says it can't be done.

[2018 Sonny]

I have a 2018 Silverado 1500 Z71 4wd and I don't have the trailer brake switch on the panel ( small storage pocket). I pulled the trim panel and plugged into the back of the pocket to a dummy plug is a harness. Is that not for being able to add the factory switch by changing out the trim panel that has the switch? Confused on this subject 

Thanks

[JimCost2014]

13 minutes ago, 2018 Sonny said:

I have a 2018 Silverado 1500 Z71 4wd and I don't have the trailer brake switch on the panel ( small storage pocket). I pulled the trim panel and plugged into the back of the pocket to a dummy plug is a harness. Is that not for being able to add the factory switch by changing out the trim panel that has the switch? Confused on this subject 

Thanks

If your truck does not have the RPO code, JL1, you can not add the factory controller.

 

PIT5241E Adding Integrated Trailer Brake Controller RPO JL1 Models Brand: Cadillac Chevrolet Chevrolet Chevrolet Chevrolet GMC GMC GMC Model: Escalade Silverado 1500 Silverado Suburban Tahoe Sierra 1500 VIN: Model Years: 2015 - 2018 2014 2015 - 2018 2015 - 2018 from All All Engine: to All All All Transmissions: All All All All 2015 - 2018 2014 Sierra Yukon Supersession Statement 2015 - 2018 2015 - 2018 All All All All This PI was superseded to update Models section. Please discard PIT5241D. Condition / Concern All All All All All All All All All All All All All All All All All All All 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. Note: Reference the latest version of PI1105 - which advises how to install an aftermarket trailer brake controller

 

[2018 Sonny]

So if I don't have the that RPO, does that mean no module and or just would need reprogramming if I switch it out.

Also why would it be there if I couldn't use it?

Thanks. 

[JimCost2014]

19 minutes ago, 2018 Sonny said:

So if I don't have the that RPO, does that mean no module and or just would need reprogramming if I switch it out.

Also why would it be there if I couldn't use it?

Thanks. 

Cheaper to put multiple plugs in the truck, even if they are not used, rather than tearing everything apart later to add it. I have the E85 plug and wiring under my truck, it is not set up for that type of fuel. The controller is the switch, all of the functions and settings are embedded in the BCM, straight from the factory, system is more than just the switch. Even dealers can not get into the program to add to the truck.

[newdude]

23 minutes ago, 2018 Sonny said:

So if I don't have the that RPO, does that mean no module and or just would need reprogramming if I switch it out.

Also why would it be there if I couldn't use it?

Thanks. 

 

 

 

 

No.  Read it again.  It means you can't add it.  Get an aftermarket controller and be done with it.  

 

PIT5241G: Adding Integrated Trailer Brake Controller RPO JL1 - (Mar 30, 2020)

 

Condition/Concern

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. 

 

[2018 Sonny]

Thanks for the info and your time. 

[C. White]

For people wandering about the JL1. Most of you are claiming that your truck isn’t factory installed JL1 but you have the JL1 module beneath the bed above the spare tire. That module you are seeing is the fuel pump driver module which is mounted to a bracket onthe underside of it. For JL1 there is a K38 chassis control module that is mounted to the top side of this bracket, a K133 trailer brake power control module that’s mounted beneath it next to the fuel pump driver module. The wiring for S76 trailer brake control switch is in fact pre wired through the dash and is terminated at the X138 connector. The wires needed to control the other two modules is not there. This very well can in fact be added after the fact providing you have factory wiring schematics and the knowledge of electrical connectors to research what connectors are used and what terminals are needed for each of the various connectors you’d be pinning the needed wiring into. There’s also some GMLAN wiring that comes from the BCM and feeds the ECM, the electronic steering gear, K17 electronic brake control module, from the K17 the GMLAN terminates with a R6A resistor. Depending on your truck, this GMLAN leaves the K17 and feeds into the K19 magnetic suspension module then passes through and feeds into the K38 before termination into the R6A.

Edited December 5, 2024 by C. White

[mikeyk101]

4 hours ago, C. White said:

For people wandering about the JL1. Most of that are claiming that your truck isn’t factory installed JL1 and that you do have the JL1 module beneath the bed above the spare tire. That module you are seeing is the fuel pump driver module which mounted to a bracket on underside of it. For JL1 there is a K38 chassis control module that is mounted to the top side of this bracket, a K133 trailer brake power control module that’s mounted beneath it next to the fuel pump driver module. The wiring for S76 trailer brake control switch is in fact pre wired through the dash and is terminated at the X138 connector. The wires needed to control the oth other to modules is not there. This very well can in fact be added after the fact providing you have factory wiring schematics and the knowledge of electrical connectors to research what connectors are used and what terminals are needed for each of the various connectors you’d be pinning the needed wiring into. There’s also some GMLAN wiring that comes from the BCM and feeds into ECM, the electronic steering gear, K17 electronic brake control module, and from the K17 the GMLAN terminates with a R6A resistor. Depending on your truck, this GMLAN leaves the K17 and feeds into the magnetic suspension module then passes through and feeds into the K38 before termination into the R6A.

 

So are you saying that it actually is possible to install the factory trailer brake controller and have it work? If so, can you provide a complete writeup as well as pictures of the project. Also can you provide the info/part numbers on the missing modules and possible wiring harnesses that prevent just installing the OEM brake controller only to find out that it doesn't work?