K 3500 Truck 4WD V8-393 6.5L DSL Turbo (1993)
Radiator Cooling Fan Motor: Description and Operation
Battery voltage is supplied to the Cooling Fan Relay by the RED (2) wire at all times and by the PNK/BLK (39) wire when the Ignition Switch is in
RUN or START. When the Cooling Fan Switch closes at 107°C (225°F), circuit 37 is grounded and the Cooling Fan Relay energizes. Battery voltage is
supplied across the Cooling Fan Motor and the Cooling Fan operates.
