WOOT! RedBox lives again! Pin #5 on the 60 way connector says 'signal ground' it wasn't grounding so we added the SIXTH chassis ground I've installed since this issue started and tapped it into the #5 pin black/white stripe wire and it fired right up
#5 blk/wht intersects with the blk/wht wire that goes to the diagnostic port, we just took a length of wire, added a lug ring (to chassis ground) and a male spade and stuck that in the diagnostic port. I know this is kinda temporary but for the real fix should I just tap the chassis ground into the blk/wht #5 a few inches back from the 60 pin connector or??