C 3500 Truck 2WD V8-454 7.4L (1990)
Wiper Motor: Testing and Inspection
Test Steps
Fig. 2 Rectangular windshield wiper motor electrical connections
Fig. 3 Connections to operate rectangular wiper motor independent of vehicle wiring
On models with pulse wipers, disconnect electrical connectors to pulse control module and connect switch and motor harnesses together. If problem is
corrected, pulse control is defective.
1.
Inspect wiring harness for breaks, loose or improper connections, and repair as needed.
2.
Ensure motor and switch are securely mounted, and properly grounded, and repair as needed.
3.
Turn ignition on and operate wipers in all switch positions, then place wiper switch in off position with wipers at top of their travel.
4.
If motor fails to operate, disconnect electrical connector to motor and check for battery voltage at terminal 2 in connector, Fig. 2, using a test
lamp.
5.
If lamp fails to light, check and repair feed circuit.
6.
If lamp lights, operate motor independent of vehicle wiring as shown in Fig. 3. If motor fails to operate, repeat test with linkage disconnected.
7.
If motor still fails to operate, motor is defective. If motor operates, repair linkage.
8.
If motor operates properly in step 6, check continuity of wiring between motor and switch. If wiring if satisfactory, replace switch.
9.
If motor will not shutoff, or if blades do not park when switch is placed in off position, check for defective park switch or open motor ground and
repair as needed.
10.
If motor operates properly in all other positions, but will not operate in delay mode, proceed as follows:
a.
Check feed circuit to pulse control and repair as needed.
b.
Check continuity of red and black wires between pulse control and wiper switch, and repair as needed.
c.
If feed circuit and wiring are satisfactory, replace pulse control.
