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

B+ -- Headlamp Washer Relay

1

1

--

--

Headlamp Washer Relay Control

1

1

2

--

Headlamp Washer Fluid Pump Control

1

1

2

--

Ground -- Headlamp Washer Relay

--

1

--

--

Ground -- Headlamp Washer Fluid Pump

--

1

--

--

1. Headlamp washer inoperative

2. Headlamp washer always ON

Circuit/System Description

When the washer switch is pressed, the windshield wiper switch sends a voltage signal through windshield washer switch signal circuit to the wiper motor module and the body control module (BCM) indicating the wash command. Every fourth time the windshield washer system is commanded ON, the BCM will initiate a headlamp wash cycle by applying B+ to the headlamp washer relay control circuit energizing the relay. The relay then closes its switch contacts applying B+ through the headlamp washer pump motor control circuit to the headlamp washer pump motor. The pump motor then runs spraying washer fluid on the headlamps. A headlamp wash cycle consists of a prewash, then a pause, and then a wash operation.

Reference Information

Schematic Reference

Instrument Cluster Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

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. Verify the windshield washers operate normally.
  2. Verify the headlamps operate normally.
  3. Verify the windshield washer fluid level is above the minimum level.
  4. If not above the minimum level, fill the reservoir and inspect for leaks.
  5. Verify the scan tool IPC Washer Fluid Level parameter is OK.

Circuit/System Testing

  1. Ignition OFF, disconnect the HEADLAMP WASH Relay.
  2. Test for less than 5 ohms between the ground circuit terminal 85 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify that a test lamp illuminates between the B+ terminal 30 and ground.
  5. If the test lamp does not illuminate, test the HEADLAMP Circuit Breaker for an open.
  6. Verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.
  7. If the test lamp illuminates, test the control circuit for a short to voltage.
  8. Connect a test lamp between the control circuit terminal 86 and the ground circuit terminal 87.
  9. Command the Headlamp Washer Relay On and OFF with a scan tool. The test lamp should turn ON and OFF when changing between commanded states.
  10. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    If the test lamp is always OFF, test the control circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the BCM.
  11. Ignition OFF, disconnect the harness connector at the headlamp washer fluid pump.
  12. Test for less than 5 ohm between the ground circuit terminal A and ground
  13. If greater than the specified range, test the ground circuit for an open/high resistance.
  14. Connect the harness connector at the headlamp washer fluid pump.
  15. Install a 3A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the headlamp washer fluid pump is activated.
  16. If it does not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp washer fluid pump.
  17. If all circuits test normal, test or replace the headlamp washer relay.

Component Test

Rear Window Washer Fluid Pump

  1. Ignition OFF, disconnect the harness connector at the headlamp 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 headlamp washer fluid pump is activated.
  4. If the headlamp washer fluid pump does not activate, replace the washer fluid pump.

Relay Test

  1. Ignition OFF, disconnect the relay.
  2. Test for 70-100 ohms between terminals 85 and 86.
  3. If the resistance is not within the specified range, replace the relay.
  4. Test for infinite resistance between the following terminals:
  5. • 30 and 85
    • 30 and 86
    • 30 and 87
    • 85 and 87
    If not the specified value, replace the relay.
  6. Install a 10A fused jumper wire between relay terminal 85 and B+. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.
  7. If greater than the specified range, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Headlamp Washer Pump Replacement
    •  Relay Replacement
    •  Control Module References for BCM replacement, programming, and setup