The body control module (BCM) controls the washer motor based on an input from the windshield washer switch, a part of the multifunction switch. The BCM monitors the washer switch through the windshield washer switch signal circuit. When the WASH switch is closed, ground is supplied to the windshield washer switch signal circuit. When this is seen, the BCM will command the windshield washer fluid pump and the low speed wipers on.

Schematic Reference

Wiper/Washer Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Wiper/Washer System Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for Scan Tool Information

1. Ignition ON, wiper switch in the OFF position, observe the scan tool Windshield Washer Switch parameter while cycling the WASH switch ON and OFF. The parameter should cycle between Active and Inactive.

⇒	If the parameter does not cycle between the specified values, refer to Multifunction Switch Circuit Malfunction.

2. Operate the washers using the WASH switch. Verify the washer pump activates and the low speed wipers turn on.
3. If the washer pump does not activate, refer to Washer Pump Circuit Malfunction.

Multifunction Switch Circuit Malfunction

1. Ignition OFF, disconnect the X1 harness connector at the multifunction switch.
2. Ignition OFF, test for less than 20 ohms of resistance between the low reference circuit terminal 7 and ground.

⇒	If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit test normal, replace the BCM.

3. Ignition ON, verify the scan tool Windshield Washer Switch parameter is Inactive.

⇒	If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the BCM.

4. Install a 3A fused jumper wire between the signal circuit terminal 6 and ground. Verify the scan tool Windshield Washer Switch parameter is Active.

⇒	If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

5. If all circuits test normal, test or replace the multifunction switch.

Washer Pump Circuit Malfunction.

1. Ignition OFF, disconnect the FRT/WSW relay.
2. Ignition ON, verify a test lamp does not illuminate between the control circuit terminal 30 and ground.

⇒	If the test lamp illuminates, test the control circuit for a short to voltage.

3. Verify a test lamp illuminates between the B+ circuit terminal 87 and ground.

⇒	If the test lamp does not illuminate, replace the underhood fuse block.

4. Verify a test lamp illuminates between the B+ circuit terminal 86 and ground.

⇒	If the test lamp does not illuminate, replace the underhood fuse block.

5. Disconnect the harness connector at the windshield washer fluid pump.
6. Test for less than 5 ohms of resistance between the ground circuit terminal B and ground.

⇒	If greater than the specified ranges, test the ground circuit for an open/high resistance.

7. Connect the harness connector at the windshield washer fluid pump.
8. Connect a 10A fused jumper wire between the B+ circuit terminal 87 and the control circuit terminal 30. Verify the windshield washer fluid pump is activated.

⇒	If the windshield washer fluid pump does not activate, test the control circuit for an open/high resistance. If the FRT/WSW fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the windshield washer fluid pump.

9. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
10. Command the windshield washer fluid pump ON and OFF with the 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 ground. If the circuit tests normal, replace the BCM.

⇒	If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

11. If all circuits test normal, test or replace the FRT/WSW relay.

Multifunction Switch

1. With the WASH switch in the open position, test for infinite resistance between the low reference terminal 7 and the signal terminal 6.

⇒	If not the specified value, replace the multifunction switch.

2. With the WASH switch in the closed position, test for less than 2 ohms of resistance between the ground terminal 7 and the signal terminal 6.

⇒	If greater than the specified range, replace the multifunction switch.

Washer Pump

1. Ignition OFF, disconnect the harness connector at the washer pump.
2. Install a 10A fused jumper wire between the control terminal A and 12 volts. Install a jumper wire between the ground terminal B and ground.
3. Verify the washer pump is activated.

⇒	If the washer pump does not activate , replace the washer pump.

Perform the after completing the diagnostic procedure