Circuit/System Testing

WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.

Rear Washer Pump Relay Control Circuit Test

Disconnect the X4 harness connector at the turn signal multifunction switch.
Ignition ON, verify the rear washer pump is not on.
- If the rear washer pump is on, test the control circuit terminal 3 for a short to voltage. If the circuit tests normal, refer to the Rear Washer Pump Circuit Test.
Install a 15A fused jumper wire between B+ and the control circuit terminal 3. Verify the rear washer pump is on.
- If the rear washer pump is not on, test the control circuit for an open/high resistance or short to ground. If the circuit tests normal replace the underhood fuse block.
If all circuits test normal, test or replace the turn signal multifunction switch.

Rear Washer Pump Circuit Test

Ignition OFF, disconnect the harness connector at the rear washer pump.
Test for less than 1.0 ohm between the ground circuit terminal B and ground.
- If greater than the specified range, test the ground circuit for an open/high resistance.
Connect a test lamp between the control circuit terminal A and the ground circuit terminal B.
Press and release the rear window washer switch. 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, test or replace the rear washer pump.