2009 Suburban 2500 - Wiring / Harness

[Jimmit]

Hi all, new to the site hoped I could find some help.

I recently purchased a 2009 2500 with 14,000 miles, outside of the usual older car that didn’t drive much maintenance, my wife wanted me to upgrade the 6 way power seats to memory seats with heat (not cooled).

After a fair amount of eBay warrior’ing I picked up a pair of seats out of an ‘08 Denali, driver and passenger door bevels and switches, a new Denali left I/P junction block (mine was missing the appropriate pins in X13), and a brand new Denali body wire harness.

This weekend I tore the interior out of the truck, swapped harnesses, swapped my leather and cushions over to the new full power frames, and put it all back together.

Fingers crossed… the truck started with no catastrophic explosions or electrical fires. As far as I know, once I get my DDM and PDM flashed the memory and heat /should/ work. However, I have lost my rear camera and power to the exterior button to open my lift-gate.

The lift-gate glass still opens fine, so it appears to be limited to the door switch only. Is this as simple as a BCM flash? The parking assist sensors all work correctly.

I do have… one plug from my dash that did not have a corresponding plug on my new harness. I believe? This is the camera? - lol. It’s a black, blue, bare connector in the passenger kickplate grey electrical pocket.

Anyone familiar with factory camera wiring able to advise on if I just need to run this cable back to the C405 connector?

 

[Jimmit]

01/09 Update:

Took a multimeter to my old harness to determine that I was correct in that my “extra plug” at the passenger kick board was the camera. I traced my new harness to find the camera doing a full loop around the truck and then disappearing up my C pillar into the ceiling somewhere. I can only assume that plug in the truck was previously unused because my old harness did not have a plug to match. After some solder and shielding work I ran a jumper from the new harness connection at the C pillar (white, Blue, un-coated) to my kick board plug and the camera was back in action.

Still need to resolve my lift gate switch. I did some investigating and I have power at the 44 fuse w/ continuity thru the fuse so at this point I’m assuming that the switch signal from the BCM is getting lost at the two “unused” wire plugs in my harness which is power lift gate capable but not installed. I’m going to look at jumping the BCM voltage across those two and see if that doesn’t resolve my swi-sue.

 

[StephenPT]

I think you might get a bit more help if this is moved to the correct forum - you're in the '21+ Electronics forum.

 

[Fless]

I think you might get a bit more help if this is moved to the correct forum - you're in the '21+ Electronics forum.

So moved. When you see a thread that should be moved, the Report link can be used to notify a mod instead of waiting for one of us to trip over it. Personally I'm clumsy enough without outside help.

EDIT: or tag one of us in the thread.

 

[swathdiver]

01/09 Update:

Took a multimeter to my old harness to determine that I was correct in that my “extra plug” at the passenger kick board was the camera. I traced my new harness to find the camera doing a full loop around the truck and then disappearing up my C pillar into the ceiling somewhere. I can only assume that plug in the truck was previously unused because my old harness did not have a plug to match. After some solder and shielding work I ran a jumper from the new harness connection at the C pillar (white, Blue, un-coated) to my kick board plug and the camera was back in action.

Still need to resolve my lift gate switch. I did some investigating and I have power at the 44 fuse w/ continuity thru the fuse so at this point I’m assuming that the switch signal from the BCM is getting lost at the two “unused” wire plugs in my harness which is power lift gate capable but not installed. I’m going to look at jumping the BCM voltage across those two and see if that doesn’t resolve my swi-sue.

You can get access to the wiring diagram for your truck at AllDataDIY.

 

[Jimmit]

You can get access to the wiring diagram for your truck at AllDataDIY.

I will take a look, Thanks for the tip!

 

[Jimmit]

01/10 Update:

You know… it’s amazing how different the logic/wiring behind the lift-gate switch is between power and manual- hahaha.

So I jumped X6-13 from the BCM to 405 B8, no change. Determined that was still needed, but then I also needed to jump X7-1 and X7-3 to B9 and B10 at 217. With that, I believe my final step to be jumping B11 at 217 down to the LGM plus J1-5 which effectively restores the switch functionality as wired for my non power lift-gate flash. While making adding a power lift-gate still reasonably plug and play with only a flash required…

Long story short, we /should/ … might? Have a lift-gate switch again tonight.

 

[Jimmit]

01/11/ Update:

Swung by the dealership for a flash, unfortunately they only managed to get the heated seats working - so I will continue to diagnose why we couldn't find the memory portion. They said that they had to use the "Aftermarket SPO" seat option. I will report back with more information when I learn of it.

 

[Jimmit]

Generally annoyed with spending the money at the dealership with regards to the pathetic feedback I received… definitely need to just buy a tuner and sps subscription.

On a positive note, the re-wiring prescribed above was successful in getting my tailgate working again. I imagine I’m a couple of wires (looking at you door harness) and a flash away from memory seats. As of 01/11, we have the most expensive heated seat upgrade ever. Well, we got heated seats /and/ power lumbar. No more turning a knob for me… worth it? Lol

 

[Geotrash]

Way to persist and figure it out! Thanks for updating us too so we now have it as part of our collective knowledge. Heated power seats and a functional liftgate = nice. Experience and knowledge gained in the process = priceless.

 

[EvergreenZ71]

01/11/ Update:

Swung by the dealership for a flash, unfortunately they only managed to get the heated seats working - so I will continue to diagnose why we couldn't find the memory portion. They said that they had to use the "Aftermarket SPO" seat option. I will report back with more information when I learn of it.

I’m impressed they were even able to do it!

I’d love to swap out the heated seats I have with heated & cooled. Never considered their value until having them in my Tahoe. But I digress…

It seems like even simple programming changes are getting too much for even the dealerships. I had to educate my local one on what afterblow was to get it programmed and they couldn’t fix the memory / towing mirror issue. How no one considered that someone would ever want a fully loaded LT with memory seats AND towing mirrors is beyond me. Dealership tried disabling the memory mirrors, but they just go to a random corner when key fob is used. I finally discovered that the best solution was to get extra fobs and set the normally used fobs as the 3rd & 4th. Use old ones for 1 & 2 to assign to the memory positions and never use them.

 

[petethepug]

Nice work and lucky wife. The rarity of the 09 2500 with that milage absolutely necessitates adding the heated and memory seats.

I assume the truck didn’t have the power fold mirror option. You really had your work cut out up fitting the options. Someone at the dealer really knew their stuff. I’d love to see some pics and know what the aftermarket SPO seat options is.

 

[Jimmit]

01/21 Update:

Spent the afternoon working on some other up-fitting.

Installed some power fold tow mirrors, fairly straight forward. Only thing that was a little obnoxious was actually just /deciding/ what I wanted to tap into. Connected into the X2-22 reverse signal for the backup light on the mirrors.

I also went ahead and installed an alpine 507 head unit, pretty pleased with it so far.

Last things outstanding is the memory function buttons… I think it may just come down to needing to find someone with a tech 2 to sit down with and try some things.

 

[Jimmit]

Realized this morning that when I unlock the truck, the previous owners memory setting are triggered… so clearly everything “works” I just need to get my DDM to talk to the MModule… that seems like a simple program issue… so I will start the hunt for a tuner and advise.

If any GM tuners in the SE wisconsin / northern IL area (I’m over by Twin Lakes) feel like troubleshooting with me give me a holler! Lol