2012 Yukon integrated brake controller not working

[i6pwr]

I'm trying to ask this on a few forums, as I'm at an impass.

2012 Yukon Denali with JL1 integrated brake controller, will not recognize the trailer.

The trailer works with an aftermarket controller on other vehicles, also, the Yukon won't recognize a 2nd trailer that is also working on another vehicle.

This is what I know....

Red wires are attached at the studs at the fuse box, fuses are good, there is 12V at each stud.

There is 12V to the brake control module above the spare tire.

There is continuity from the blue wire at the module, to the rear of the 7-pin.

7-pin is clean on all ends.

Brake lights work on trailer.

No stored codes.

I've also tried a new module and new gain switch.

Still no change.

All fuses are good.


Anyone run into this? Especially odd since there are no error messages.

 

[Rand]

Has the trailer brake controller ever worked on this yukon?

 

[i6pwr]

I don't know. I bought it used last year and this is the 1st time I've tried it with trailer brakes.

I had to unravel the 12V leads and secure them to the posts, so I'm assuming I am the 1st to try.

May need a BCM update or flash....not sure.

 

[Rand]

Seems to be a ton of people having your issue.. most pulled out hair then wired up an aftermarket trailer brake controller.

 

[BrandonV]

If you use the DIC under Vehicle Information is there anything about the integrated trailer braking system at all?

 

[i6pwr]

Nothing in the DIC.

Yeah, I have seen a few dead ends that ended with an aftermarket controller...hopefully I can avoid that.

 

[spasm3]

This may be of help but he had a trailer brake fault message.

 

[BrandonV]

Did you happen to inspect or look at the relay module (20904439)? These things have been a constant PITA in the past all across GM vehicles.

 

[GMBoy]

I was the plant quality engineer for electrical/chassis at that time period and we had major issues with that module. You say you replaced it but was it new and was it programmed with the latest software? Don't waste time with a used one - they are all at risk.

 

[i6pwr]

Did you happen to inspect or look at the relay module (20904439)? These things have been a constant PITA in the past all across GM vehicles.

Yes, that was the part number I used when I replaced mine, was an AC Delco part.

I was the plant quality engineer for electrical/chassis at that time period and we had major issues with that module. You say you replaced it but was it new and was it programmed with the latest software? Don't waste time with a used one - they are all at risk.

Very cool pedigree.

I did get the part from a dealer, I hear ya on that, better to pay a few extra $$ to ensure it's brand new especially when most of these cannot be returned.

Honestly as of yesterday, I wasn't aware it needed to be re-programmed...looks like that might be in the cards.

I have a Tech 2 but doesn't seem that I will have the ability to re-program it myself.

Looks like in the past 10 years since this vehicle was new, I am the first to try to use and hookup the 12V to the integrated brake controller. The battery has also been replaced twice since new which may or may not have caused any issues.

 

[GMBoy]

Yes, that was the part number I used when I replaced mine, was an AC Delco part.



Very cool pedigree.

I did get the part from a dealer, I hear ya on that, better to pay a few extra $$ to ensure it's brand new especially when most of these cannot be returned.

Honestly as of yesterday, I wasn't aware it needed to be re-programmed...looks like that might be in the cards.

I have a Tech 2 but doesn't seem that I will have the ability to re-program it myself.

Looks like in the past 10 years since this vehicle was new, I am the first to try to use and hookup the 12V to the integrated brake controller. The battery has also been replaced twice since new which may or may not have caused any issues.

Your Tech 2 can do it but it is very cumbersome. Here is the best bet - go to https://www.acdelcotds.com/subscriptions# and for just $40 you get 2 years of programming for ALL your vehicles modules. Simple and fast. You will need the correct J2534 interface but they are available cheap and a laptop.

From the GM Service Manual:

Trailer Brake Control Module Programming and Setup
If the Trailer Brake Control Module or the combination Fuel Pump/Trailer Brake Control Module is replaced or needs to be reprogrammed, refer to Service Programming System (SPS). The calibrations for either of these modules are accessed through the FPCM Fuel Pump Control Module selection in the supported controllers list. The Trailer Brake Control Module is not listed as a separate choice. Once the Fuel Pump Control Module is selected, the SPS system will download the proper calibration for the vehicle based on the VIN entered.

 

[i6pwr]

I have the CAT 5 to serial, and a serial to USB.

I'm all in if I can get this to work.

Thank you for your help!

 

[i6pwr]

Current progress is I had to get a 24hr subscription to the tis according to GM TDS tech.

So later today I plan on attempting this reprogram.

 

[i6pwr]

You will need the correct J2534 interface but they are available cheap and a laptop.

I wanted to touch on this, as I thought it was something else.

Would the J2534 be the safer method? I spoke with the tech dept at GM TDS, and they gave me a 24hr link to the tis2000 so I could use the Tech 2 as a pass through.

Should I just source a J2534 instead?

Any recommendations on one until I source a MDI1 or 2?

 

[GMBoy]

I wanted to touch on this, as I thought it was something else.

Would the J2534 be the safer method? I spoke with the tech dept at GM TDS, and they gave me a 24hr link to the tis2000 so I could use the Tech 2 as a pass through.

Should I just source a J2534 instead?

Any recommendations on one until I source a MDI1 or 2?

I prefer the MDI (the 1st version is fine for your use. The 2nd version is necessary for certain models 2021+). but go with what you have and see before spending more money.

 

[clinebarger]

I use a Autel J2534 all the time with zero issues. Tech 2's can be finicky on some CAN vehicles.

 

[i6pwr]

Current progress is....I picked up the Tripp Lite DB9 USB to serial adapter, the laptop connected to tis recognized the Yukon and I reprogrammed the FPCM with the current software. Turns out the FPCM did have the current version but I updated anyway.

Unfortunately the Yukon still does not recognize the trailer.

I have verified that I have 12V to the brake control relay, continuity from the relay's blue wire to the rear of the 7-pin connector, and a good ground.

Not sure what to check at this point.

 

[i6pwr]

I wanted to add, if I disconnect the factory brake control connector, the connector at the slide lever, and start the engine, I do not get a check trailer brake warning message.

 

[wtd]

Current progress is....I picked up the Tripp Lite DB9 USB to serial adapter, the laptop connected to tis recognized the Yukon and I reprogrammed the FPCM with the current software. Turns out the FPCM did have the current version but I updated anyway.

Unfortunately the Yukon still does not recognize the trailer.

I have verified that I have 12V to the brake control relay, continuity from the relay's blue wire to the rear of the 7-pin connector, and a good ground.

Not sure what to check at this point.

You might try load testing the blue wire from the relay to the 7 pin connector. Continuity will just show that some of the wires are connected but not necessarily that it can carry a load. You could have a partially broken wire or even corrosion in the wiring.

 

[CapitalTruck]

Yes, that was the part number I used when I replaced mine, was an AC Delco part.



Very cool pedigree.

I did get the part from a dealer, I hear ya on that, better to pay a few extra $$ to ensure it's brand new especially when most of these cannot be returned.

Honestly as of yesterday, I wasn't aware it needed to be re-programmed...looks like that might be in the cards.

I have a Tech 2 but doesn't seem that I will have the ability to re-program it myself.

Looks like in the past 10 years since this vehicle was new, I am the first to try to use and hookup the 12V to the integrated brake controller. The battery has also been replaced twice since new which may or may not have caused any issues.

I could be wrong, but I thought the factory controller was pre-hooked up? Could you be bypassing something by having hooked up that red wire that maybe is for aftermarket controllers only? Just throwing spaghetti against the wall here. One red wire is for 12v at the hitch (“charge” trailer battery), other red is for trailer brake controller.