Factory integrated brake controller not recognizing trailer.

[swathdiver]

Not sure if this is correct, but in this pic, between ground (pin B), and Pin C, I have .9 ohms.

View attachment 377064


Also, is this a relay for the brake controller?

View attachment 377065

Number 1 and 2 refer to the controller on the dash and this is the connector:

I don't know what that relay is for; it is not the SSR.

 

[dkad260]

Thanks for all the help....but do you have the pinout for the brake controller?

Which is ground?

Sorry, I don't have the diagram for the brake controller.

I went ahead and verified I had continuity between the 7 pin blue and the blue terminal at the TBCM, also ground was good and I have good ground at the trailer.

 

[dkad260]

Going back to an earlier post, I did not see a SSR near the ABS pump.

Here's the pump..

And another module behind it, didn't see any relays.

 

[dkad260]

Are you referring to this, that's above what I believe is the fuel pump controller. Mine is mounted above the spare tire along the cross members.

 

[dkad260]

Well, I figured worst case I would have some spare parts. I went and installed a new module and new gain switch....still no change. I have 12V at the module, and the blue wire is good from the module to the 7-pin connector.

At a loss for the moment...

If anyone want's to PM me and set up a phone call feel free...

 

[swathdiver]

Updated earlier post with pinout, sorry, forgot about that.

Ok, if the module is bad, you just cannot plug in a new one and carry on, it has to be programmed through ACDelco's TDS system. If you don't have a laptop and subscription to TDS and the interface and all that, it may be less expensive and time consuming to have a local GM dealer do it for you.

There are some photos of where the SSR is in this old thread:

Where Is My Solid State Relay (SSR)???

I showed the 2 places it will be in my jul14 post with photos, the 2nd photo shows it is on the top (fig. 16), that is directly from the gm service manual.

www.tahoeyukonforum.com

Was looking for weeks until someone found it for me! LOL

 

[dkad260]

Mine wasn't along the frame rail, but above the spare tire between the cargo floor and the crossmember....this is what I replaced..

 

[swathdiver]

Mine wasn't along the frame rail, but above the spare tire between the cargo floor and the crossmember....this is what I replaced..

I would love to learn their logic in placing those things in different places! LOL

Yours is right where the books say it's supposed to be! LOL

 

[dkad260]

The relay could have been EASILY placed near the receiver. GM really went out of their way to hide it. One bolt was in the open, the other is under the FPCM so you have to remove the FPCM to access the 2nd bolt.

The bolts to remove the FPCM are a T30 and are ABOVE the mounting plate.

It gets better....if you don't have a slim 1/4 bit ratchet, you have to remove the mounting plate that holds the FPCM and trailer relay, in which those bolts are ABOVE the cross members....threaded down into the crossmember.

Complete insanity.

 

[swathdiver]

The relay could have been EASILY placed near the receiver. GM really went out of their way to hide it. One bolt was in the open, the other is under the FPCM so you have to remove the FPCM to access the 2nd bolt.

The bolts to remove the FPCM are a T30 and are ABOVE the mounting plate.

It gets better....if you don't have a slim 1/4 bit ratchet, you have to remove the mounting plate that holds the FPCM and trailer relay, in which those bolts are ABOVE the cross members....threaded down into the crossmember.

Complete insanity.

How is it working out today?

 

[dkad260]

Just getting ready to start..just got back home.

Going to go over all the steps first. According to GM TDS tech, I needed a 24 hr subscription to tis to use the Tech 2 as a pass through....apparently the TDS doesn't recognize the handheld Tech 2 right now?? Weird.

 

[swathdiver]

Just getting ready to start..just got back home.

Going to go over all the steps first. According to GM TDS tech, I needed a 24 hr subscription to tis to use the Tech 2 as a pass through....apparently the TDS doesn't recognize the handheld Tech 2 right now?? Weird.

@Joseph Garcia

I think Joe said to click past that to the next page and then you can pick it. Haven't done it this way yet myself.

 

[dkad260]

I'm at this screen, when I select "Service Programming System" in the Tech 2, I can only go up to 2007.

I can select the Tech 2, but get this message on both re-program, and replace and re-program.

 

[swathdiver]

See if this thread helps until the cavalry arrives: https://www.tahoeyukonforum.com/thr...-gm-techline-connect-for-tech-2-users.129842/

@sunureu13 @91RS @Fubar0715

 

[dkad260]

Thanks @swathdiver good info.

No progress yet, going to get on a call again this AM and see what we can do.

This has definitely been a frustrating endeavor.

 

[dkad260]

My generic USB to serial is one issue, going to get a Tripp Lite cable and then we are dealing with a possible Win 11 issue but need the different cable first.

 

[Joseph Garcia]

It seems that the only current fully successful approach is to get on the phone with their support Techs and have them issue a 24 hour license back to the original TDS program and help walk you through the process to complete the programming/reprogramming.

 

[dkad260]

It seems that the only current fully successful approach is to get on the phone with their support Techs and have them issue a 24 hour license back to the original TDS program and help walk you through the process to complete the programming/reprogramming.

Yes, that's what I had done this AM. They were very helpful and I did a screen share with the agent and she discovered my USB to serial adapter was not compatible.

Once this process has (hopefully) been resolved, I will surely source a MDI or something for future programming.

 

[dkad260]

Update...

I picked up the Tripp Lite USB to serial adapter, and the tis recognized the Yukon.

I successfully re-installed the current software to the FPCM, but unfortunately the Yukon still does not recognize the trailer.

Not sure what else to check.

 

[dkad260]

As I'm progressing through this dillema, trying to diagnose the integrated system, I keep getting this...

At the same time I have this...

If there's a fault, would there be a code set?