Wipers and Washers
2-71
3443584
Windshield Washer System
The BCM controls the windshield wash operation and
windshield wash activated wiper operation. When the
BCM detects the activation of the momentary
windshield wash control switch, it activates its washer
pump relay drive output which supplies battery power
to the coil of the washer pump relay. This energizes the
relay, which switches battery power to the pump motor.
The BCM will also activate continuous low speed
windshield wipes as described above. Upon
deactivation of the windshield wash control switch, the
wiper control module (BCM) shall deactivate the wash
motor and will also park the wiper motor as described
above unless the drip wipe feature is enabled. On some
vehicles the drip wipe feature will be enabled and
cause the system to provide additional wiping of the
windshield after the switch has been released and fluid
is no longer being applied. The front wash feature may
attempt to detect a stuck switch. When enabled,
activation of the wash feature shall be limited to
10 seconds.
On vehicles with the Rear Wash feature a single
reversing wash motor may be utilized for both the front
and rear wash operation. In this system the wash motor
is operated in one direction to spray fluid on the front
windshield and then operated in the reverse direction to
spray fluid on the rear window. The BCM Controls the
reversing wash motor through two High Side Drive
outputs. One controls the Front Wiper Motor Relay and
one controls the Rear Wiper Relay.
2021 - Silverado 4500HD, 5500HD, and 6500HD Electrical Body Builder Manual
