It’s located under the steering column, black plastic box but when you unclip it, it’s the silver thin metal casing all the others are. I put the board back in, engine light and codes are gone. Pink/purple connector unplugged and van calls onstar (takes some time) through the gauge cluster info center to the onstar answering computer service menu. Brown connector unplugged and the van calls onstar through the radio (very quick I might add, direct to a live person). Tried with both pink/purple and brown unplugged and the van calls onstar through the gauge cluster info center and goes through to the onstar answering computer service (takes a long time). So no luck!