Here’s the wiring diagrams for the BCM - note there are 8 separate fused inputs from both the underhood fuse block and the instrument panel fuse block. Disconnect the BCM connectors and use a test light to check which power inputs are good.

 

Great info. I still believe the ignition circuit needs checked, starting with correct install of the ignition switch and wires at starter solenoid.

 

So before the bcm not getting power issue, all lights on truck would pulse/flash. Headlights, taillights, interior lights literally every light on the truck. Batt, alt, all tested great. I’m wondering if the pulsing lights and loss of constant power to bcm are connected or may help someone on here who has way more knowledge than myself possibly figure out where to look for my wire problem. Also all lights on truck are still pulsing.