Looks like the main issue is with the instrument cluster and bcm. I pieced together the bcm wiring pinout from autozone. Found out why the montana swap is so simple and widely done, as it uses the same bcm as quite a few other L67 vehicles such as the grand prix.
Unfortunately for me, the only other vehicle that uses the exact bcm is the buick rendezvous (which makes sense because it's basically a cousin).
Strangely, the BCM in the 05 impala and monte carlo L67s uses three out of four identical connectors, and uses class2 data just like the Aztek for almost every system. I'm thinking best case scenario, the pcm from the impala will communicate with the gauge cluster and bcm and it'll be a simple swap. Worst case, I'm going to have to figure out how to swap the impala bcm in the Aztek and figure out what features I can save and what I have to give up.
Anyone have the BCM pinout to an 05 impala? Can't find them anywhere...
