GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2008 🢒 Envoy - 2WD 🢒 Diagnostic Navigation 🢒 Vehicle Diagnostic Information 🢒 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 Reference Voltage

1

1

--

--

Rear Wiper Washer Switch Signal

1

1

1

--

Rear Washer Pump Relay Control

B3811

B3811

--

--

Rear Washer Pump Control

2

2

3

--

Rear Washer Pump Ground

--

2

--

--

1. Rear wiper washer inoperative

2. Rear washer pump inoperative

3. Rear washer pump always on

Circuit/System Description

Battery positive voltage is supplied to the coil and switch sides of the rear washer relay. The body control module (BCM) energizes the relay by grounding the relay coil through the relay control circuit. When the relay is energized, the relay switch is closed and battery positive voltage is supplied to the washer pump control circuit.

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 motor operates using the rear washer switch.
    2. ⇒If the rear wiper does not operate normally, refer to Rear Wiper System Malfunction .
  2. If the rear washer pump does not operate properly, refer to the Rear Washer Pump Circuit Test.

Circuit/System Testing

Rear Washer Pump Circuit Test

  1. Ignition OFF, disconnect the REAR/WPR relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the washer pump control circuit terminal 30 and ground.
    3. ⇒If the test lamp illuminates, test the control circuit for a short to voltage.
  3. Disconnect the harness connector at the rear washer pump.
  4. Test for less than 1.0 ohm between the rear washer pump ground circuit terminal A and ground.
    5. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  5. Connect the harness connector at the rear washer pump.
  6. Connect a 20A fused jumper wire between the B+ circuit terminal 87 and the washer pump control circuit terminal 30. Verify the rear washer pump is activated.
    7. ⇒If the rear washer pump does not activate, test the control circuit for an open/high resistance. If the circuit tests normal, test or replace the rear washer pump.
  7. Connect a test lamp between the B+ circuit terminal 85 and the relay control circuit terminal 86.
  8. Operate the rear washer switch ON and OFF. The test lamp should turn ON and OFF when changing between the commanded states.
    9. ⇒If the test lamp is always ON, test the relay 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.
  9. If all circuits test normal, test or replace the REAR/WPR relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Rear Window Washer Pump Replacement
    •  Control Module References for BCM replacement, programming, and setup