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

Battery Positive Voltage

1

1

--

--

Ignition 3 Voltage

1

1

--

--

Washer Fluid Heated Control Switch Signal

3

1

1

--

Windshield Washer Switch Signal

4

1

4

--

Washer Fluid Heated Control Switch LED Supply Voltage

2

2

1

--

Washer Solvent Heater Assembly Ground

--

1

--

--

Washer Solvent Heater Assembly Logic Ground

--

1

--

--

1. Windshield Washer Solvent Heater Malfunction

2. Windshield Washer Solvent Heater Indicator Inoperative

3. Windshield Washer Solvent Heater Indicator Always ON

4. Windshield Wiper System Malfunction

Circuit/System Description

The heated windshield washer fluid operation is controlled by a separate switch located on the turn signal/multifunction switch. When the heated washer fluid switch is pressed, ground is momentarily applied through the switch contacts and the heated washer fluid switch signal circuit to the windshield washer solvent heater assembly. In response to this signal, the washer solvent heater assembly then applies battery voltage to its internal washer fluid heating elements and pulls the heated washer fluid indicator control circuit low commanding the DIC to display the HEATING WASH FLUID WASH WIPES PENDING message. The washer fluid is then heated as it passes through the heater assembly to the windshield.

Reference Information

Schematic Reference

Wiper/Washer Schematics

Connector End View Reference

Wiper/Washer Connector End Views

Electrical Information Reference

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

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Testing

Windshield Washer Solvent Heater Malfunction

  1. Ignition OFF, disconnect the C1 harness connector at the windshield washer solvent heater assembly.
  2. Test for less than 5 ohms of resistance between the ground circuit terminal 2 and ground.
  3. If greater than 5 ohms, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify that a test lamp illuminates between the battery positive voltage circuit terminal 1 and ground.
  5. If the test lamp does not illuminate, test the battery positive voltage circuit for a short to ground or an open/high resistance.
  6. Ignition OFF, disconnect the C2 harness connector at the windshield washer solvent heater assembly.
  7. Test for less than 5 ohms of resistance between the ground circuit terminal 4 and ground.
  8. If greater than 5 ohms, test the ground circuit for an open/high resistance.
  9. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 6 and ground.
  10. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  11. Connect a test lamp between the heated washer fluid switch signal circuit terminal 1 and battery voltage.
  12. The test lamp should turn ON and OFF while pressing and releasing the heated washer fluid switch.
  13. If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the turn signal/mulitfunction switch.
    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 turn signal/mulitfunction switch.
  14. Ignition ON, verify that a test lamp does not illuminate between the heated washer fluid indicator control circuit terminal 2 and ground.
  15. If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the instrument panel cluster (IPM).
  16. If all circuits test normal, test or replace the windshield washer solvent heater assembly.

Windshield Heated Washer Fluid Indicator Inoperative

  1. Ignition OFF, disconnect the C2 harness connector at the windshield washer solvent heater assembly.
  2. Ignition ON, install a 3A fused jumper wire between the heated washer fluid indicator control circuit terminal 2 and ground. Verify the DIC displays the HEATING WASH FLUID WASH WIPES PENDING message.
  3. If the message is not displayed, test the control circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the instrument panel cluster (IPM).
  4. If all circuits test normal, replace the windshield washer solvent heater assembly.

Windshield Heated Washer Fluid Indicator Always On

  1. Ignition OFF, disconnect the C2 harness connector at the windshield washer solvent heater assembly.
  2. Ignition ON, the DIC should not display the HEATED WASHER FLUID WASHER SYSTEM OFF message.
  3. If displayed, test the heated washer fluid indicator control circuit for a short to ground. If the circuit tests normal, replace the instrument panel cluster.
  4. If all circuits test normal, replace the windshield washer solvent heater assembly.

Component Testing

Heated Washer Fluid Switch

  1. Ignition OFF, disconnect the C4 harness connector at the turn signal/multifunction switch.
  2. Test for infinite resistance between the signal terminal 1 and the ground terminal 2 with the switch in the open position.
  3. If less than infinite, replace the turn signal/multifunction switch switch.
  4. Test for less than 3 ohms between the signal terminal 1 and the ground terminal 2 with the switch in the closed position.
  5. If greater than 3 ohms, replace the turn signal/multifunction switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Turn Signal Multifunction Switch Replacement
    •  Windshield Washer Solvent Heater Replacement
    •  Control Module References for IPC replacement, programming and setup