K 2500 Truck 4WD V8-5.7L VIN R (1996)
Four Wheel Drive Indicator Lamp: Description and Operation
When the Ignition Switch is in RUN and the Four-Wheel Drive Control Lever is engaged, the Transfer Case Switch closes and Battery Voltage is
supplied across the Front Axle actuator. The Front Axle actuator energizes and the Four-Wheel Drive gears are meshed. This meshing action of the
Four-Wheel Drive gears closes the Front Axle Switch, and Battery Voltage is supplied through CKT 1695 across the Four-Wheel Drive indicator
lighting the bulb.
Battery Voltage is also supplied through the Front Axle Switch contacts and CKT 1695 to the Rear-Wheel or Four-Wheel Antilock Brake module. This
will modify the Antilock Braking System operation in 4WD mode.
A Transfer Case Relay is used on one-ton vehicles with Four-Wheel Drive. This Relay is de-energized when the vehicle is in 4WD mode. From the
Transfer Case relay, Voltage is supplied to the Transfer Case synchronizer until 4WD mode is selected.