Savvy_Fox42

Two big things with the swap, the LBZ uses a high speed can line for the engine to trans to glow plug module connection that also goes to the obd2 port. I ran those into the escalade dash harness. Mine was not 4wd, but AFAIK you should just overlay the wires for the 4x4 switch setup and be fine. Second, I had to de pin a few of the wires from the large escalade brake / chassis control connector for the rear lights and abs stuff. The escalade i got my interior from was a 6.0 AWD model so the connectors might be different. PM me if you need more wiring help.

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?

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?

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.

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.

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.

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.

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.