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.

Circuit/System Description

During windshield wiper/washer system WASH operation, the wiper/washer module controls the operation of both, the wiper motor and the windshield washer pump. The windshield wiper/washer module is part of the windshield wiper motor cover and controls wiper motor operation. The accessory voltage supplied to the windshield wiper motor assembly is used to operate the wiper motor in all modes. The windshield wiper motor is a 2 speed motor and is operated at low speed in all modes except HIGH. When the wiper/washer switch is activated, battery voltage is applied through the switch contacts, a series of resistors, and through the wiper switch signal circuits to the wiper/washer module. The voltage level of these signal circuits determine the windshield wiper/washer modes of operation.

Reference Information

Schematic Reference

Wiper/Washer 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 Testing

Ignition ON, press and release the windshield washer switch. The washer pump and wiper motor should operate for as long as the switch is pressed, and the wiper motor will continue to operate several cycles after the switch is released.

If the wiper motor is inoperative during wash mode, refer to Windshield Wiper System Malfunction
If the washer pump is inoperative during wash mode, refer to Washer Pump Control Circuit Test.

Washer Pump Control Circuit Test

  1. Ignition OFF, disconnect the harness connector at the windshield washer fluid pump.
  2. Test for less than 1 ohm of resistance between the ground circuit terminal B and ground.
  3. If greater than the specified value, repair the ground circuit for an open/high resistance.
  4. Ignition ON, verify that a test lamp illuminates between the washer pump control circuit terminal A and ground while pressing the washer switch.
  5. If the test lamp does not illuminate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the windshield wiper washer module.
  6. If all the circuits test normal, test or replace the windshield washer fluid pump.

Washers Always On

  1. Remove the WPR fuse from the underhood fuse block. The washer pump should turn OFF.
  2. If the washer pump does not turn OFF, test the washer pump control circuit for a short to voltage.
  3. If all the circuits test normal, test or replace the windshield wiper washer module.

Component Testing

Multifunction Switch

  1. With the ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
  2. Test the resistance between terminals H and L. Rotate the wiper switch and compare the resistance readings to the values in the Windshield Wiper Switch Values table below for MIST, each DELAY and LOW speed.
  3. If the resistance is not within the specified range, replace the turn signal/multifunction switch.
  4. Test for infinite resistance between terminals H and K while rotating the wiper switch to MIST, each DELAY and LOW speed positions.
  5. If the less than infinite, replace the turn signal/multifunction switch.
  6. Test for less than 5 ohms of resistance with the wiper switch in the High speed position..
  7. If greater than the specified value, replace the turn signal/multifunction switch.
  8. Test for infinite resistance between terminals H and N while rotating the wiper switch to MIST, each DELAY and LOW speed positions.
  9. If less than infinite, replace the turn signal/multifunction switch.
  10. Test for less than 5 ohms of resistance while pressing the WASHER switch.
  11. If greater than the specified value, replace the turn signal/multifunction switch.

Important: If the switch tests open in any switch position other than Off, test the wiper/washer switch signal circuits for a short to voltage before replacing the switch.

Wiper Switch Values

Switch Position

Resistance

Off

Infinite

Mist

300-364 Ω

Delay 1

3.48K-4.25K Ω

Delay 2

2.52K-3.08K Ω

Delay 3

1.78K-2.18K Ω

Delay 4

1.17K-1.44K Ω

Delay 5

697-851 Ω

Low

2.52K-3.08K Ω

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Turn Signal Multifunction Switch Replacement
    •  Windshield Wiper Motor Replacement
    •  Control Module References for BCM replacement, setup, and programming