Wash, Mist, Delay 1-5, Low, and Park are all low speed wiper motor functions controlled by the body control module (BCM). The BCM energizes the ON/OFF WPR relay in order to operate the wiper motor at low speed. The high speed wiper function operates independent of the wiper switch signal 1 circuit and any BCM output. During high speed wiper operation the wiper switch signal 2 circuit directly energizes the HI/LOW WPR relay and energizes the ON/OFF WPR relay through the wiper diode #90.

If the wiper motor runs at high speed during the low speed modes replace the wiper diode #90.

Schematic Reference

Wiper/Washer Schematics

Connector End View Reference

Wiper/Washer Connector End Views

Electrical Information Reference

Scan Tool Reference

Wipers Inoperative All Modes

1. Install a scan tool and display the Wiper Delay Input parameter in the BCM data list.
2. Ignition ON, the scan tool should display 0.5-3.0 volts in switch positions Mist, Delay 1-5, Low, and High.

⇒	If the scan tool displays 0.0 volts in the listed switch positions test the voltage supply circuit to the windshield wiper washer switch for an open or short to ground or the windshield wiper switch signal 2 and the washer pump control circuits for a short to ground.

3. With the windshield wiper switch to the Low speed position the Front Wipers Active parameter in the BCM inputs data list should display On for several seconds.

⇒	If the scan tool does not display On test the windshield wiper motor high and low speed circuits for a short to ground. If the circuits test normal replace the ON/OFF WPR relay.

4. Disconnect the windshield wiper motor connector.
5. Verify that a test lamp will illuminate when connected from battery voltage to the ground circuit.

⇒	If the test lamp does not illuminate repair the windshield wiper motor ground circuit for an open/high resistance.

6. If all the circuits test normal replace the windshield wiper motor.

Delay or Low Speed Wipers Inoperative

1. Install a scan tool and display the Wiper Delay Input parameter in the BCM data list.
2. Ignition ON, the scan tool should display 0.5-3.0 volts in switch positions Mist, Delay 1-5, Low, and High.

⇒	If the scan tool displays 0.0 volts in any of the listed switch positions test the windshield wiper switch signal 1 circuit for an open or short to ground and perform the windshield wiper washer switch low speed component test. If the circuit and switch test normal replace the body control module.

3. With the wiper switch in the High speed position verify that the Front Wipers Active parameter in the BCM Inputs data list is On.

⇒	If the scan tool does not display On test the wiper relay control circuit for an open/high resistance. If the circuit tests normal replace the body control module.

4. Disconnect the windshield wiper motor connector.
5. Connect a test lamp between the low speed control circuit and the ground circuit.
6. The test lamp should illuminate with the windshield wiper switch in the Low speed position.

⇒	If the test lamp does not illuminate test the wiper motor low speed circuit and underhood fuse block for an open/high resistance.

7. If all the circuits test normal replace the windshield wiper motor.

High Speed Wipers Inoperative

1. Operate the wiper switch to the High speed position.
2. With the ignition on verify that the Front Wipers Active parameter in the BCM inputs data list is On.

⇒	If the Front Wipers Active parameter is not On perform the windshield wiper washer switch high speed component test, test the windshield wiper switch signal 2 circuit and underhood fuse block for an open/high resistance. If the circuit and switch test normal replace the wiper diode #90.

3. Disconnect the windshield wiper motor connector.
4. Verify that a test lamp will illuminate when connected between the high speed control circuit and the ground circuit.

⇒	If the test lamp does not illuminate test the wiper motor high speed circuit for an open/high resistance. If the circuit tests normal replace the HI/LOW WPR relay.

5. If all the circuits test normal replace the windshield wiper motor.

Low Speed Wipers Always On

1. Ignition ON, verify that the Wiper Relay Command parameter on the BCM outputs data list is Off.

⇒	If the scan tool displays On test the windshield wiper switch signal 1 circuit for a short to voltage and perform the windshield wiper washer switch low speed component test. If the circuit and switch test normal replace the body control module.

2. Verify that the Front Wipers Active parameter on the BCM inputs data list is Off.

⇒	If the scan tool displays On test the wiper relay control circuit for a short to voltage. If the circuit tests normal replace the BCM.

3. Verify that the wipers stop when the ON/OFF WPR relay is removed.

⇒	If the wipers remain on test the windshield wiper motor low speed control circuit for a short to voltage.

4. If all the circuits test normal replace the ON/OFF WPR relay.

High Speed Wipers Always On

1. Verify that the Front Wipers Active parameter on the BCM inputs data list is Off.

⇒	If the scan tool displays On test the windshield wiper washer switch signal 2 circuit for a short to voltage and perform the windshield wiper washer switch high speed component test.

2. Disconnect the windshield wiper motor connector.
3. Wiper switch OFF, verify that a test lamp will not illuminate when connected between the wiper motor high speed control circuit and ground.

⇒	If the test lamp illuminates repair the wiper motor high speed control circuit for a short to voltage. If the circuit tests normal replace the underhood fuse block.

Washers Inoperative

1. Display the Washer Switch parameter on the BCM Inputs data list.
2. Ignition ON, verify that the Washer Switch parameter is On while the washer switch is pressed.

⇒	If the scan tool displays Off perform the windshield washer switch component test. If the switch tests normal repair the windshield washer pump control circuit from the switch to the BCM for an open/high resistance.

3. Disconnect the windshield washer pump connector.
4. A test lamp connected between the washer pump control circuits should illuminate while the washer switch is pressed.

⇒	If the test lamp does not illuminate repair the windshield washer pump control circuit from the BCM to the pump or the ground circuit for an open/high resistance.

5. If all the circuits test normal replace the windshield washer pump.

Washers Always On

1. Disconnect the steering column harness to instrument panel (I/P) harness inline connector C201.
2. Ignition ON, the windshield washers should not be ON.

⇒	If the windshield washers remain on repair the windshield washer pump control circuit for a short to voltage.

3. If the windshield washers turn off replace the windshield wiper washer switch.

Windshield Wiper Washer Switch High and Wash circuits.

1. Disconnect the steering column harness to I/P harness inline connector C201.
2. Connect a DMM from the accessory voltage supply circuit terminal to the windshield wiper switch signal 2 circuit terminal in the steering column connector half.
3. The DMM should indicate continuity while the wiper switch is in the High speed position.

⇒	If the DMM does not display 0-2 ohms replace the windshield wiper washer switch.

4. The DMM should indicate no continuity while the wiper switch is in any position other than High.

⇒	If the DMM does not display infinite resistance replace the windshield wiper washer switch.

5. Connect a DMM from the accessory voltage supply circuit terminal to the windshield washer pump control circuit terminal.
6. The DMM should indicate continuity while the windshield washer switch is pressed.

⇒	If the DMM does not display 0-2 ohms replace the windshield wiper washer switch.

7. The DMM should indicate no continuity when the windshield washer switch is released.

⇒	If the DMM does not display infinite resistance replace the windshield wiper washer switch.

Windshield Wiper Washer Switch Low Speed Circuit

Important: If the switch tests open in any switch position other than Off test wiper switch signal 1 circuit for a short to ground before replacing the switch.

1. Disconnect the Steering Column harness to I/P harness inline connector C201.
2. Connect a DMM from the accessory voltage supply circuit terminal to the windshield wiper switch signal 2 circuit terminal in the steering column connector half.
3. Operate the windshield wiper switch from Off to Mist, Delay 1 through 5, Low, and High.

⇒	If the DMM does not display at or near the resistance values provided replace the windshield wiper washer switch.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.