New to programming, recently purchased FlashscanV2. I have an '03 5.3 that is in my '87 S10. I have the complete engine harness, pcm, and underhood pdc. I have thinned out my harness as per LT1swap.com (mostly stand alone) but am keeping emissions. I also have the donor dash harness with bcm (not installed). However I have cut out the c1 underhood connector to mate my stock chassis harness at the firewall to the 5.3 underhood pdc. I have the DLC wired up in the engine bay currently just to see if everything is online and powering up. I can not communicate with the pcm via FlashscanV2 or a generic scan tool. According to alldata the bcm tells the pcm to turn on when certain criteria are met. I am wondering if I need to wire in the bcm just so I can communicate and turn off the VATS and bcm etc? Is there simply another wire that I need power to in order to turn on the pcm? How do the bench programmers do it? I am willing to make/modify a bench harness if need be but that's essentially what I have isn't it? I will be verifying all my powers/grounds tonight per the wiring diagrams as well as i'll post the hardware/part # for my pcm. Trying to give enough detail but not get too lengthy, thanks in advance. Build thread on www.v8s10.org under the same username. Right now i'm just wanting to get rid of VATS and nuisance codes, no internal engine mods, will tune for CAI and exhaust once its running. Pcms is 12582605 and hardware is 12580786