Anyone done an escalade interior swap?

Savvy_Fox42 · November 25, 2021

Im looking to see if anyone has completed a swap in of the interior of a gmt 800 Cadillac Escalade (ESV) into a diesel truck, namely an lbz. I have a parts escalade with all the harnesses, but am running into issues getting it all to work and line up electrically. All the panels transfer over nicely. Thx in advance y'all.

shakenfake · November 25, 2021

Yes everything is possible to do except for the cluster. If you want the cluster you will need a custom built one

Savvy_Fox42 · November 25, 2021

Does the underwood fuse box need to be swapped? I swapped in the escalade dash harness, but not all the plugs seem to line up for the original plugs. I'm starting from a 2007 3500 classic wt model, so manual everything.

shakenfake · November 26, 2021

Not that I remember no

Savvy_Fox42 · November 27, 2021

I'm assuming I have to use the escalade harness then. Do I just hook up all the plugs that match and leave the ones that don't? Or do I need to split the harness and just add what's different in the escalade harness to my existing dash harness? Or am I overthinking it all and just have to use the original truck harness and only the escalade body harness? Thanks for the help.

shakenfake · November 28, 2021

Well some of the escalade harness bits may not match up such as the climate control. There are like 3 different climate controls and you would need the same BCM.

Just use the escalade harness as that will be the easiest way imo, you do not need to change any of the engine portion only the dash stuff.

Savvy_Fox42 · December 3, 2021

Ok, I tried to fire up the duramax today, but it would just start and die 3 seconds later. I tried with both BCMs, and got the same behavior from both. No visible security light on the dash, although i got few lights on the dash as it were. The, i think, passlock light turned on and went out each time the key was inserted and turned.

The escalade dash harness only had 2 of the 4 small plugs matching. Am i missing something, or is a 2005 escalade harnness not compatible enough to run a 2007 silverado classic?

Sorry for the delayed replies. Caught the covid last week and its been hard fighting.

shakenfake · December 3, 2021

Hmm I think the issue is in your PCM. It needs VATS turned off to be able to swap BCMs like that, although it may spaz out with the Caddy BCM since the VINs are different but it should not

JimCost2014 · December 3, 2021

I would think it is from the hallucinating induced from COVID 19 (which ever strain it is this week), maybe give it some time and try with a clear mind

Savvy_Fox42 · December 3, 2021

Ok. Some update. The start and stall doesn't seem to be a fault of the bcm. I swapped the original harness back into the truck and it started properly. But if i disconnect connector C100 under the fuse box, it does the start and stall behavior. After consulting online wiring diagrams, it seems the most important pins are 3 communication lines that are specific to the 6 speed Allison. So it looks like as long as i can re pin the connector to have those comm. lines, it should start and run with the escalade main harness. Will update if i am able to pull it off.

shakenfake · December 3, 2021

Good luck let us know. I suggest try using your stock BCM instead of the Escalade just because the VINs won't match and it will trigger VATS

Savvy_Fox42 · December 5, 2021

Ok. I added the 3 pins per the manuals shown wiring, backed up with tracing the old harness. Still the same thing happening with start and die. To recap what i have done, i left the original fuse box, swapped the escalade dash harness into the truck. The 16 pin harness under the dash had the 3 comm pins added that are listed for the Allison 6 speed. I used the silverados original BCM. I can crank it up and it starts and shuts off 2 seconds later. This implies a VATS issue right? Another issue stands that the only light that comes on the cluster is the CEL. No passlock, no gauges, no driver info in the display. Ive checked all the fuses and they are fine. Any idea what I am missing or have done wrong?

Savvy_Fox42 · December 5, 2021

I figured it out. I didnt have the lower relay block installed. The one that is down by the brake pedal. There apparently are multiple ground splices in the relay block so the BCM wasnt powering up and VATS was being triggered. Now to start putting in escalade pieces and repinning the two other connectors to match my options list. Ill keep this thread updated and add some pictures when i can.

Would anyone want a writeup on the swap once i get it on the road again?

shakenfake · December 6, 2021

Sure why not. If I wasn't so lazy I'd do this on my 99 so I can have the dual climate control and the better gauge cluster...

DaddyBlue · March 6, 2023

Todd, is your 3500 4x4? Did you have to add any transfer case wiring? Did you leave the Escalade Electronic BrakesLarge plug unhooked? I am currently working on a Escalade Platinum interior swap into my 2500HD Duramax 4x4. I am looking for pointers. Thanks Trevor