Wiper Motor Circuit Test
WARNING: This page is about a different car, the 2009 GMC Sierra, 2009 GMC Cab & Chassis Sierra, 2009 Chevrolet Silverado, and 2009 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.
- Disconnect the harness connector at the windshield wiper motor.
- Test for less that 1 ohm between the wiper motor ground circuit terminal 5 and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Connect a test lamp between the low speed motor control circuit terminal 1 and ground.
- Ignition ON, command the Wiper Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the underhood fuse block.
- If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the underhood fuse block.
- Connect a test lamp between the high speed motor control circuit terminal 4 and ground.
- Wiper switch in the LOW position, command the Wiper High Speed Relay ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
- If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the underhood fuse block.
- If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the underhood fuse block.
- If all circuits test normal, replace the windshield wiper motor.