GMC Rally G2500 (1985-1995) 6.5l (vin f), data link connector circuit

1995 VFTC BLK WIRE DATA LINK CONNECTOR (BEHIND LEFT SIDE OF SHIPPING PANEL) DIAGNOSTIC TEST ENGINE GROUND ORG/BLK WIRE POWERTRAIN CONTROL MODULE (BEHIND LEFT SIDE OF SHIPPING PANEL) SERIAL DATA WHT/BLK WIRE