GMC Vandura P3500 (1985-1997) Heater circuit

BLOWER MOTOR BLOWER RESISTOR (ENGINE COMPARTMENT, ON BLOWER HOUSING) BRN WIRE FUSE BLOCK HEATER BLOWER SWITCH HOT IN RUN HTR A/C FUSE LO MED LT BLU WIRE OFF HI ORG/ WIRE YEL WIRE