I am reinstalling the dash on my 06 lbz duramax 2500 chevrolet and i have it all hooke up except one light purple and blue plug that is on a stretch of wires that run from under the dash around the left side past the fuse panel and from there i dont know. I can turn the truck on, but it will shut off after 2seconds. The only light that is working on the dash is the engine light lol. Need some help, could that plug be screwing everything up? if so where does it go? i will keep digging but i cant find a place to plug it in..

it goes into the bcm reason truck shutting off is cause its contains the pass lock it goes to kinda the back in the center if that makes sense that should get u running again