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

Wiper Motor Supply

1

1

--

--

Wiper Switch 12-Volt Reference

2

2

--

Wiper Switch Signal 1

2

2

--

Wiper Switch High Signal

3

4

--

--

Wiper Switch Ground

--

4

--

--

Wiper Motor Ground

--

1

--

--

1. Wiper motor inoperative in all modes

2. Wiper motor inoperative in all low speed modes

3. Wiper motor always on at high speed

4. Wiper motor inoperative in high speed

Circuit/System Description

Accessory voltage and ground is supplied to the windshield wiper motor and provides the power for operating the wiper motor and logic power to the wiper motor module. The WASH, MIST, LOW, and DELAY modes are controlled by the windshield wiper/washer switch through a series of internal resistors. The windshield wiper switch supply voltage circuit is a 12-volt reference from the wiper motor module to the wiper/washer switch, and the switch position determines the point on the resistor assembly where the reference voltage is applied. The windshield wiper switch signal 1 circuit supplies the voltage from the resistor assembly to the wiper motor module and the signal voltage determines the operating mode. High speed operation is controlled by the windshield wiper/washer switch through the windshield wiper switch high signal circuit. The windshield wiper switch high signal circuit is supplied 12 volts by the wiper motor module and when the wiper/washer switch is turned to the HIGH position the windshield wiper switch high signal circuit is grounded through the switch ground circuit.

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 Verification

Ignition ON, verify wiper motor operation in all switch positions.

If the wiper motor is inoperative in all modes, refer to Wiper Motor/Module Circuit Test.
If the wiper motor is inoperative in high or all low speed modes only, refer to Wiper Motor Switch Circuit Test.
If the wiper motor is inoperative in delay modes, low, or mist, but operates in wash mode, test or replace the turn signal/multifunction switch.

Circuit/System Testing

Wiper Motor Switch Circuit Test

  1. Disconnect the X2, X3 harness connectors at the turn signal/multifunction switch.
  2. Test for less than 1.0 ohm of between the ground circuit terminal A X2 and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, test for 11.0-13.0 volts between the 12-volt reference circuit terminal J X3 and ground.
  5. If less than the specified range, test the 12-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the wiper motor cover.
  6. Install a 3A fused jumper wire between the signal circuit terminal K X3 and the 12-volt reference circuit terminal J X3. Ignition ON, verify the wiper motor operates in the wash mode.
  7. If the wiper motor does not operate, test the signal circuit for an open/high resistance or short to ground. If the circuit tests normal, refer to Wiper Motor/Module Circuit Test.
  8. Install a 3A fused jumper wire between the signal circuit terminal H X3 and ground. Ignition ON, verify the wiper motor operates in the high speed mode.
  9. If the wiper motor does not operate, test the signal circuit for an open/high resistance. If the circuit tests normal, refer to Wiper Motor/Module Circuit Test.
  10. If all circuits test normal, test or replace the turn signal/multifunction switch.

Wiper Motor/Module Circuit Test

  1. Ignition OFF, disconnect the harness connector at the windshield wiper motor cover.
  2. Test for less than 1.0 ohm between the ground circuit terminal M and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Verify that a test lamp illuminates between the B+ circuit terminal F and ground.
  5. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  6. Remove the wiper motor cover.
  7. Connect the harness connector at the windshield wiper motor cover.
  8. Connect a test lamp between the circuit board terminals T1 and T3.
  9. Ignition ON, wiper switch in low, verify the test lamp turns on for 15 seconds.
  10. If the test lamp does not turn on, replace the wiper motor cover.
  11. If all circuits test normal, test or replace the windshield wiper motor.

Component Testing

  1. Ignition OFF, disconnect the X2, X3 harness connectors at the turn signal/multifunction switch.
  2. Test the resistance between terminals H X3 and J X3. Rotate the wiper switch and compare the resistance readings to the values in the Windshield Wiper Switch Values table below for WASH, MIST, each DELAY and LOW speed.
  3. If the resistance is not within the specified range, replace the turn signal/multifunction switch.
  4. Wiper switch in HIGH position, test the resistance between terminals K X3 and A X2. The reading should be between 0.0-1.0 ohm.
  5. If the resistance is not within the specified range, replace the turn signal/multifunction switch.

Switch Position

Resistance

Off

Infinite

Wash

0.0-1.0 ohm

Mist

360-420 ohms

Delay 1

0.980-1.40K ohms

Delay 2

1.80-1.86K ohms

Delay 3

3.00-3.60K ohms

Delay 4

5.70-5.76K ohms

Delay 5

8.40-8.46K ohms

Low

360-420 ohms

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Turn Signal Multifunction Switch Replacement
    •  Windshield Wiper Transmission Replacement
    •  Windshield Wiper Motor Cover Replacement