Chevrolet Cab & Chassis C3500 (1989-2000) 6.5l (vin f), data link connector circuit

4-WHEEL ABS BLK/WHT WIRE DATA LINK CONNECTOR DIAGNOSTIC TEST FOUR-WHEEL ANTI-LOCK BRAKE MODULE (NEAR MASTER CYLINDER) FUEL PUMP FUEL PUMP PRIME FUEL PUMP RELAY GRY WIRE ORG/ WIRE POWERTRAIN CONTROL MODULE (UNDER RIGHT END OF I/P) REAR WHEEL ABS RED WIRE RWAL MODULE (LEFT REAR ENGINE COMPT) VEHICLE SPEED INPUT SERIAL DATA VEHICLE SPEED INPUT VEHICLE SPEED OUTPUT VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF I/P) WHT WIRE WHT/BLK WIRE