GM Service Manual Online
For 1990-2009 cars only

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 Window Wiper Motor B+

2

1

1

--

Windshield Washer Fluid Pump Control

1

1

2

--

Windshield Washer Relay Control

2

1

B3873 00

--

Windshield Washer Switch Low Reference

--

1

1

--

Windshield Washer Fluid Pump Ground

--

1

--

--

1. Washer Inoperative

2. Washers Always ON

Circuit/System Description

The rear wiper washer control module controls the washer motor based on an input from the windshield washer switch. When the WASH switch is closed, ground is supplied to the windshield washer switch signal circuit. When this is seen, the rear wiper washer control module will command the rear washer fluid pump on.

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

Rear wiper switch in the WIPER position. The rear wiper should turn ON.

If the rear wiper does not turn ON, refer to Rear Wiper System Malfunction

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the window wiper/washer switch rear.
  2. Ignition ON, wiper/washer switch rear in the WASHER position, test for ignition voltage between the signal circuit terminal 1 and ground.
  3. If not than the specified value, test for a short to ground or an open/high resistance.
  4. Ignition OFF, connect the harness connector at the rear window wiper/washer module. Disconnect the harness connector at the rear window washer fluid pump.
  5. Test for less than 10 ohms between the ground circuit terminal 1 and ground.
  6. If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Ignition ON, wiper/washer switch rear in the WASHER position, verify a test lamp illuminates between the control circuit terminal 2 and ground.
  8. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance.
    If the test lamp illuminates test or replace the rear window washer fluid pump.
  9. If all circuits test normal, test or replace the rear window wiper motor.

Component Testing

Wiper/Washer Switch

  1. With the WASH switch in the open position, test for infinite resistance between the low reference terminal 1 and the signal terminal 2.
  2. If not the specified value, replace the wiper/washer switch rear.
  3. With the WASH switch in the closed position, test for less than 2 ohms between the ground terminal 1 and the signal terminal 2.
  4. If greater than the specified range, replace the wiper/washer switch rear.

Washer Pump

  1. Ignition OFF, disconnect the harness connector at the washer pump.
  2. Install a 10A fused jumper wire between the control circuit terminal 1 and 12 volts. Install a jumper wire between the ground circuit terminal 2 and ground.
  3. Verify the washer pump is activated.
  4. If the washer pump does not activate , replace the rear window washer fluid pump.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Windshield Wiper and Washer Switch Replacement
    •  Rear Window Wiper Motor Replacement
    •  Rear Window Washer Pump Replacement