I tried to read the codes on a 99 Blazer, but the scanner didn't power up. It's not the scanner because it worked on another '00 Blazer. I probed pins #5 & #16 on the vehicle side & didn't get any voltage. This is with the key in the run position. I tried cycling the key a couple of times.
Does anybody have a schematic for the OBD <-> BCM interface, so I can start debugging this further?

Thanks

 

IIRC, it's powered by the same fuse as the cig lighter. Have you checked that one?

 

Thanks. We got the code pulled.

 

That's good, but what was the solution?

 

Blown cigarette lighter fuse.