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Wiper System Testing

Following are tests that will help to diagnose the hard wired components and circuits of the windshield wiper system. However, these tests may not prove conclusive in the diagnosis of this system. In order to obtain conclusive testing of the windshield wiper system, the Programmable Communications Interface (PCI) data bus network and all of the electronic modules that provide inputs to, or receive outputs from the windshield wiper system components must be checked.

The most reliable, efficient, and accurate means to diagnose the windshield wiper system requires the use of a DRB scan tool and the proper Diagnostic procedures. The DRB scan tool can provide confirmation that the PCI data bus is functional, that all of the electronic modules are sending and receiving the proper messages on the PCI data bus, and that the wiper on/off and wiper high/low relays are being sent the proper hard wired outputs by the Body Control Module (BCM) for them to perform their windshield wiper system functions.

WARNING: ON VEHICLES EQUIPPED WITH AIR-BAGS, REFER TO AIRBAGS SYSTEMS BEFORE ATTEMPTING ANY STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENT DIAGNOSIS OR SERVICE. FAILURE TO TAKE THE PROPER PRECAUTIONS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY.

1. Check the fused ignition switch output (run/accessory) fuse in the junction block. If OK, go to Step 2. If not OK, repair the shorted circuit or component as required and replace the faulty fuse.
2. Turn the ignition switch to the On position. Check for battery voltage at the fused ignition switch output (run/accessory) fuse in the junction block. If OK, go to Step 3. If not OK, repair the open fused ignition switch output (run/accessory) circuit to the ignition switch as required.
3. Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Disconnect the instrument panel wire harness connector from the wiper and washer (right multi-function) switch connector receptacle. Connect the battery negative cable. Turn the ignition switch to the On position. Check for battery voltage at the fused ignition switch output circuit cavity of the instrument panel wire harness connector for the wiper and washer switch. If OK, go to Step 4. If not OK, repair the open circuit to the junction block fuse as required.
4. Disconnect the 22-way instrument panel wire harness connector from the Body Control Module (BCM). Check for continuity between the windshield wiper switch return circuit cavity of the instrument panel wire harness connector for the wiper and washer switch and a good ground. There should be no continuity. If OK, go to Step 5. If not OK, repair the shorted windshield wiper switch return circuit to the BCM as required.
5. Check for continuity between the windshield wiper switch return circuit cavities of the instrument panel wire harness connector for the wiper and washer switch and the 22-way instrument panel wire harness connector for the BCM. There should be continuity. If OK, go to Step 6. If not OK, repair the open windshield wiper switch return circuit to the BCM as required.
6. Check for continuity between the windshield wiper switch mux circuit cavity of the instrument panel wire harness connector for the wiper and washer switch and a good ground. There should be no continuity. If OK, go to Step 7. If not OK, repair the shorted windshield wiper switch mux circuit to the BCM as required.
7. Check for continuity between the windshield wiper switch mux circuit cavities of the instrument panel wire harness connector for the wiper and washer switch and the 22-way instrument panel wire harness connector for the BCM. There should be continuity If OK, reconnect the 22-way instrument panel wire harness connector to the BCM connector receptacle and go to Step 8. If not OK, repair the open windshield wiper switch mux circuit to the BCM as required.
8. Refer to Wiper and Washer switch Diagnosis. If the wiper and washer switch tests OK, reconnect the instrument panel wire harness connector to the wiper and washer switch connector receptacle and go to Step 9. If the wiper and washer switch does not test OK, replace the faulty wiper and washer switch.
9. If the problem being diagnosed is that the wiper blades do not park, but all other functions are OK, go to Step 10. If the problem being diagnosed is that the wipers will operate in low speed when an intermittent delay is selected and the wiper blades do not park, go to Step 11. If the problem being diagnosed is no wiper operation in any mode, go to Step 14. If the problem being diagnosed is that the wipers will not operate in high speed, go to Step 18.
10. Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Backprobe the fused ignition switch output (V6) circuit cavity of the left headlamp and dash wire harness connector at the windshield wiper motor. Reconnect the battery negative cable. Turn the ignition switch to the On position. Check for battery voltage. If OK, go to Step 11. If not OK, repair the open fused ignition switch output (V6) circuit to the junction block wiper system circuit breaker as required.
11. Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Disconnect the left headlamp and dash wire harness connector from the windshield wiper motor connector receptacle. Disconnect the 52-way (C2) instrument panel wire harness connector from the junction block connector receptacle. Check for continuity between the wiper park switch sense circuit cavity of the left headlamp and dash wire harness connector for the windshield wiper motor and a good ground. There should be no continuity. If OK, go to Step 12. If not OK, repair the shorted wiper park switch sense circuit as required.
12. Check for continuity between the wiper park switch sense circuit cavities of the left headlamp and dash wire harness connector for the windshield wiper motor and the 52-way (C2) instrument panel wire harness connector for the junction block. There should be continuity If OK reconnect the 52-way (C2) instrument panel wire harness connector to the junction block connector receptacle and go to Step 13. If not OK, repair the open wiper park switch sense circuit as required.
13. Reconnect the left headlamp and dash wire harness connector to the windshield wiper motor connector receptacle. Reconnect the battery negative cable. Turn the ignition switch to the On position. Backprobe the wiper park switch sense circuit cavity of the left headlamp and dash wire harness connector at the windshield wiper motor. Check for battery voltage. With the wiper switch in the Low or High position, the meter should switch between battery voltage and zero volts. Turn the wiper switch to the Off position and the meter should read battery voltage until the wiper blades park, and then read a steady zero volts. If OK, use a DRB scan tool and the proper Diagnostic procedures to diagnose the BCM. If not OK, replace the faulty windshield wiper motor.
14. Backprobe the ground circuit cavity of the left headlamp and dash wire harness connector at the windshield wiper motor. Check for continuity to a good ground. There should be continuity If OK, go to Step 15. If not OK, repair the open ground circuit to ground as required.
15. Remove the wiper system circuit breaker from the junction block. Reconnect the battery negative cable. Turn the ignition switch to the On position. Check for battery voltage at the fused ignition switch output (run/accessory) cavity for the wiper system circuit breaker in the junction block. If OK, go to Step 16. If not OK, repair the open fused ignition switch output (run/accessory) circuit to the ignition switch as required.
16. Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Install the wiper system circuit breaker in the junction block. Reconnect the battery negative cable. Turn the ignition switch to the On position. Check for battery voltage at the fused ignition switch output (V6) circuit cavity for the wiper system circuit breaker in the junction block. If OK, go to Step 17. If not OK, replace the faulty wiper system circuit breaker.
17. Refer to Wiper On/Off Relay Diagnosis. If the wiper on/off relay tests OK, go to Step 18. If the wiper on/off relay does not test OK, replace the faulty wiper on/off relay
18. Refer to Wiper High/Low Relay in the Diagnosis and Testing. If the wiper high/low relay tests OF[, replace the faulty wind-shield wiper motor. If the wiper on/off relay does not test OK, replace the faulty wiper high/low relay.
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