AIphabet

Ok, so I want to replace my bcm because it's been messing with my electricals. The door chimes have been coming on randomly and i have dash lights and headlights on after key is off. I am pretty sure it's the bcm. Would it be ok if I were to swap a used one? I know it has to be flashed. What kind of things would I need to look for in a used one? Does the colored block on the part matter?

Really I need answers. I have zero clue on how to use this site. I recently overhauled my 4.8 vortec for my 03 sierra 1500. I hookerd every single connection up and went to crank and it clicks once and never tries anything again. No noises from starter or nothing. I have had some other issues too, a few select lights on my dash stay on after the truck is turned off completely and the key is out, specifically the brake light, seatbelt light and security light. The DTRL stay on too. Relay for the DTRL clicks when you switch them from high beams to low beams, the fuel pump relay clicks when switching from acc to on and a high pitch ringing can be heard from the passenger side of the engine bay. I'm really at a loss for what's wrong. Could it be that I pinched a wire? a bad ground? a short? every wire still has the protective sleeving. i also had the wiring harness wayyy out of the way when I put my engine back in.