Savannah, I pulled C0286, I checked all the pins, 1,2,19 & 20 were closed to ground, the rest were open. I'm digging thru the Rave service and electrical manuals...getting an education.
I checked the pink wire from the OBD port to the C0286 header, that was alive and well. The header and all it connections are all alive and well.

I guess there's a diagnostic for the computer itself in the RAVE. If there are any other solutions, I would really appreciate hearing them.

note: the pin order seems to be reversed...as in 1,2, 19 & 20 are common in the header, but the diagram shows them on separate sub-headers...maybe it's just me...
Thanks, ...again...

 

I would try to unplug the C0286, and then make a connection just from pin 16 (OBDII connector) and pin 20 (ECU). This takes everything else off the circuit, and you can't do much with their codes without a special reader anyway. If still no joy, and you have verfied connection from ECU all the way to OBDII port, then that does leave the ECU. But swapping it needs to get the BCU in sync with it, and may require a dealer or advanced shop vist.

 

Hey, Savannah! So, I did as you suggested, almost, everyhting is good. I haven't got to the 20 pin on the ECM YET. I'm going to do that shortly. I suspect the wire is good.'
So, on to the ECM replacement, there's a Rover wrecker in Myrtle Beach, SC. They have a ECM for $60, if I got the corresponding BCU along with the ECM, it should be all good...YES? Thereby taking the dealership out of the pic...plus they're over 100 miles away...

APPRECIATE YOUR HELP! Thanks

PS 20 yrs ago I grafted a "94 4.3 vortec into a '84 S10 Blazer, that was a lesson, I had forgotten...& it only had ONE COMPUTER...! Back 2 school!

 

Sounds like a plan. Hold down hood switch before powering back up, the old BCU may remember that it was "armed" and try to alarm and immobilize you.

 

Thanks again, again! I ordered them today. I'll squak you when I get them in. Have great holiday weekend. And remember why!