GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 Enclave 🢒 Body Systems 🢒 Wipers and Washers 🢒 Rear Wiper Washer System Malfunction

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Rear Wiper/Washer Switch Ignition Voltage

1

1

--

--

Rear Washer Switch Signal

1

1

2

--

Rear Window Washer Pump Control

3

3

4

--

Rear Window Washer Pump Ground

--

3

--

--

1. Rear Window Wiper/Washer System Inoperative

2. Rear Window Wiper/Washer Always On

3. Rear Window Washer Pump Inoperative

4. Rear Window Washer Pump Always On

Circuit/System Description

The rear washer is activated based on an input from the rear washer switch. When the wiper portion of the rear wiper/washer switch is closed, B+ is applied to the REAR/WSW relay indicating rear washer operation is requested. With B+ applied to the relay coil, the relay is energized and B+ is supplied to the washer pump.

Reference Information

Schematic Reference

Wiper/Washer Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Rear Wiper/Washer System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification
  1. Ignition ON, verify the rear wiper operates normally using the rear wiper switch.
    2. ⇒If the rear wipers do not operate properly, refer to Rear Wiper System Malfunction.
  2. Operate the rear washers using the rear washer switch. The rear washer pump should activate.

Circuit/System Testing
  1. Ignition OFF, disconnect the REAR/WSW relay.
  2. Ignition ON, verify a test lamp does not illuminate between the control circuit terminal 87 and ground.
    3. ⇒If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Ignition OFF, test for less than 5 ohms between the ground circuit terminal 86 and ground.
    4. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 30 and ground.
    5. ⇒If the test lamp does not illuminate, replace the I/P fuse block.
  5. Install a test lamp between the control circuit terminal 85 and ground.
  6. Command the rear washers ON and OFF using the rear washer switch. The test lamp should turn ON and OFF when changing between the commanded states.
    7. ⇒If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, test or replace the multifunction switch (WDA/Z88) or I/P switch assembly (W49).
    ⇒If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the multifunction switch (WDA/Z88) or I/P switch assembly (W49).
  7. Ignition OFF, disconnect the harness connector at the rear window washer fluid pump.
  8. Test for less than 20 ohms between the ground circuit terminal A and ground.
    9. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  9. Connect the harness connector at the rear window washer fluid pump.
  10. Connect a 20A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the rear window washer fluid pump is activated.
    11. ⇒If the rear window washer fluid pump does not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the rear window washer fluid pump.
  11. If all circuits test normal, test or replace the REAR/WSW relay.

Component Testing

Multifunction Switch (WDA/Z88)

  1. Ignition OFF, disconnect the X1 harness connector at the multifunction switch.
  2. Rear washer switch OFF, test for infinite resistance between the ignition terminal 4 and the control terminal 6.
    3. ⇒If not the specified value, replace the multifunction switch.
  3. Rear washer switch ON, test for less than 2 ohms between the ignition terminal 4 and the control terminal 6.
    4. ⇒If greater than the specified range, replace the multifunction switch.

I/P Switch Assembly (W49)

  1. Ignition OFF, disconnect the harness connector at the I/P switch assembly.
  2. Rear washer switch OFF, test for infinite resistance between the ignition terminal 6 and the control terminal 12.
    3. ⇒If not the specified value, replace the I/P switch assembly.
  3. Rear washer switch ON, test for less than 2 ohms between the ignition terminal 6 and the control terminal 12.
    4. ⇒If greater than the specified range, replace the I/P switch assembly.

Rear Window Washer Fluid Pump

  1. Ignition OFF, disconnect the harness connector at the rear window washer fluid pump.
  2. Install a 20A fused jumper wire between the control terminal B and 12 volts. Install a jumper wire between the ground terminal A and ground.
  3. Verify the rear window washer fluid pump is activated.
    4. ⇒If the rear window washer fluid pump does not activate, replace the rear window washer fluid pump.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Rear Window Washer Pump Replacement
    •  Turn Signal Multifunction Switch Replacement
    •  Instrument Panel Electrical Center or Junction Block Replacement