D 250 Pickup V6-239 3.9L (1989)
Wheel Speed Sensor: Description and Operation
RWAL Speed Sensor
Rear Wheel Anti-Lock Brake System
PURPOSE
The speed sensor is used to transmit speed and rate of deceleration information to the control module by means of a small AC voltage.
OPERATION
This voltage is generated by magnetic induction by passing a toothed sensor ring (exciter ring) past a stationary magnetic sensor.
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The toothed exciter ring is pressed onto the differential case.
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The sensor is mounted at the top of the rear axle housing directly over the gear-type exciter ring.