Windshield Wiper System Malfunction
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Windshield Wiper System Malfunction
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Diagnostic Fault Information
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Circuit
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Short to Ground
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Open/High Resistance
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Short to Voltage
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Signal Performance
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Windshield Wiper High Speed Relay B+
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1, 2
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1, 2
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-
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-
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Windshield Wiper Switch Low Signal
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1
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1
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1
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-
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Windshield Wiper Switch High Signal
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4
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2
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2
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-
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Windshield Wiper Motor Park Switch Signal
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3
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3
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-
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-
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Front Wiper Relay Control
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B3715 02
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1, 2
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4
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-
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Windshield Wiper High Speed Relay Control
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B3875 02
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2
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B3875 01
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-
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Windshield Wiper High Speed Relay Control
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2
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2
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4
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-
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Front Wiper Motor Low Speed Control
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1
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1
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4
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-
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Windshield Wiper Switch Low Reference
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-
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1, 2
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1, 2
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-
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Windshield Wiper Motor Ground
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-
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1, 2, 3
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-
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-
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Front Wiper Relay Ground
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-
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1
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-
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-
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1. Delay or Low Speed Wipers Inoperative
2. High Speed Wipers Inoperative
3. Wipers Do Not Park
4. Wipers Always ON
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Circuit/System Description
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The body control module (BCM) controls the wiper motor based on input from the windshield wiper/washer switch. The BCM monitors the wiper/washer switch through two separate signal circuits and a ground circuit. The windshield wiper switch high signal circuit is used to determine high speed wiper operation, the windshield wiper switch low signal is used to determine low speed, intermittent, and mist operation through the use of a resistor ladder, and the windshield washer switch signal circuit is used to determine washer operation.
The BCM controls the windshield wiper motor through two output controls, controlling two relays which determine the desired wiper speed, high or low.
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
Scan Tool Reference
Control Module References
for scan tool information
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Circuit/System Verification
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1.
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Ignition ON, windshield wiper/washer switch in the OFF position, verify the scan tool Windshield Washer Switch parameter is Inactive.
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3.
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Wiper switch in the OFF position, verify the scan tool Windshield Wiper Switch parameter is Off.
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4.
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If not the specified value, refer to the Windshield Wiper/Washer Switch Circuit Test.
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5.
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Wiper switch in the OFF position, verify the scan tool Windshield Wiper High Speed Switch parameter is Inactive.
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6.
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If not the specified value, refer to the Windshield Wiper/Washer Switch Circuit Test.
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7.
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Wiper switch in the LO position, verify the scan tool Windshield Wiper Switch parameter is Low.
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8.
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If not the specified value, refer to the Windshield Wiper/Washer Switch Circuit Test.
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9.
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Wiper switch in the HIGH position, verify the scan tool Windshield Wiper High Speed Switch parameter is Active.
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10.
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If not the specified value, refer to the Windshield Wiper/Washer Switch Circuit Test.
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11.
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Wiper switch in the INT position, observe the scan tool Windshield Wiper Switch parameter while cycling the delay adjustment switch from long delay to short delay. The parameter should cycle between D1 and D5 as each delay position is selected.
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12.
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If not the specified value, test or replace the windshield wiper/washer switch.
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13.
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Wiper switch in the LO position, verify the windshield wipers are cycling at the low speed.
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14.
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If the wipers are not operating at low speed, refer to the Windshield Wiper Motor Circuit Test.
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15.
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Wiper switch in the HIGH position, verify the windshield wipers are cycling at high speed.
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16.
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If the wipers are not operating at high speed, refer to the Windshield Wiper Motor Circuit Test.
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17.
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Observe the scan tool BCM Wiper Park Switch parameter. The reading should display Active when the wipers are parked and Inactive with the wipers ON or out of the park position.
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18.
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If the Wiper Park Switch parameter is always Active or Inactive or the wipers do not park, refer to the Wiper Park Circuit Test.
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Windshield Wiper/Washer Switch Circuit Test
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1.
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Ignition OFF, disconnect the X1 harness connector at the S82 windshield wiper/washer switch.
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2.
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Verify a test lamp illuminates between the low reference circuit terminal 2 and B+.
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3.
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If the test lamp does not illuminate, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K9 BCM.
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4.
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Ignition ON, test for B+ between the signal cirucit terminal 1 and ground.
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5.
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If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
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6.
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Ignition ON, test for B+ between the signal cirucit terminal 3 and ground.
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7.
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If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
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8.
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Ignition On, test for 10 V between the signal circuit terminal 5 and ground.
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9.
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If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
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10.
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If greater than the specified value, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
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11.
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If all circuits test normal, test or replace the S82 windshield wiper/washer switch.
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Windshield Wiper Motor Circuit Test
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1.
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Ignition OFF, disconnect KR12B windshield wiper relay.
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2.
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Test for less than 5 Ω between the ground circuit terminal 85 and ground.
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3.
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If greater than the specified range, test the ground circuit for an open/high resistance.
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4.
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Test for less than 5 Ω between the ground circuit terminal 87A and ground.
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5.
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If greater than the specified range, test or replace the X50A underhood fuse block.
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6.
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Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 87 and ground.
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7.
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If the test lamp does not illuminate, test or replace the X50A underhood fuse block.
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8.
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Install a test lamp between the control circuit terminal 86 and ground.
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9.
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Command the low speed wipers ON and OFF using the S82 windshield wiper/washer switch. The test lamp should turn ON and OFF when changing between the commanded states.
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10.
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If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.
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11.
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If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.
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12.
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Ignition OFF, disconnect the KR12C windshield wiper speed control relay.
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13.
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Test for less than 5 Ω between the control circuit terminal 30 of the KR12B windshield wiper relay and control circuit terminal 30 of the KR12C windshield wiper speed control relay.
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14.
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If greater than the specified range, test or replace the X50A underhood fuse block.
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15.
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Connect the KR12B windshield wiper relay.
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16.
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Test for less than 5 Ω between the control circuit terminal 30 of the KR12C windshield wiper speed control relay and ground.
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17.
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If greater than the specified range, test or replace the KR12B windshield wiper relay.
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18.
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Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 85 of the KR12C windshield wiper speed control relay and ground.
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19.
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If the test lamp does not illuminate, test or replace the X50A underhood fuse block.
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20.
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Install a test lamp between the control circuit terminal 30 of the KR12C windshield wiper speed control relay and ground.
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21.
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Command the LOW speed wipers ON using the S82 windshield wiper/washer switch. The test lamp should illuminate when commanding the LOW speed wipers ON.
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22.
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If the test lamp does not illuminate, replace the KR12B windshield wiper relay.
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23.
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Connect a test lamp between control circuit terminal 86 of the KR12C windshield wiper speed control relay and B+.
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24.
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Turn the high speed wipers ON and OFF using the S82 windshield wiper/washer switch. The test lamp should turn ON and OFF when changing between the commanded states.
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25.
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If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 BCM.
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26.
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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 K9 BCM.
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27.
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Ignition OFF, connect the KR12C windshield wiper speed control relay and disconnect the X1 harness connector at the M75 windshield wiper motor.
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28.
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Test for less than 5 Ω between the ground circuit terminal C and ground.
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29.
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If greater than the specified range, test the ground circuit for an open/high resistance.
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30.
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Connect a test lamp between control circuit terminal E and ground.
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31.
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Turn on the ignition and turn the low speed wipers ON and OFF using the S82 windshield wiper/washer switch. The test lamp should turn ON and OFF when changing between the commanded states.
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32.
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If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, test or replace the KR12C windshield wiper speed control relay.
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33.
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If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the KR12C windshield wiper speed control relay.
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34.
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Connect a test lamp between control circuit terminal D and ground.
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35.
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Turn the high speed wipers ON and OFF using the S82 windshield wiper/washer switch. The test lamp should turn ON and OFF when changing between the commanded states.
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36.
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If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, test or replace the KR12C windshield wiper speed control relay.
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37.
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If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the KR12C windshield wiper speed control relay.
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38.
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If all circuits test normal, test or replace the M7 windshield wiper motor.
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Wiper Park Circuit Test
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1.
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Ignition OFF, disconnect the harness connector at the windshield wiper motor.
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2.
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Ignition ON, test for B+ between signal circuit terminal B and ground.
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3.
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If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the K9 BCM.
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4.
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If the circuit tests normal, test or replace the windshield wiper motor.
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Windshield Wiper/Washer Switch
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1.
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Disconnect the harness connector at the S82 windshield wiper/washer switch.
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2.
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With the S82 windshield wiper/washer switch in the HIGH position, test for less than 5 Ω between the low reference terminal 2 and the signal terminal 1.
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3.
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If greater than the specified value, replace the S82 windshield wiper/washer switch.
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4.
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While cycling the S82 windshield wiper/washer switch through each delay and speed position, test for the specified resistance between the low reference terminal 2 and the signal terminal 3 .
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Note
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If the switch tests open in any switch position other than OFF, test the signal circuits for a short to voltage before replacing the switch.
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Wiper Switch Values
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Switch Position
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Resistance
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Off
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Infinite
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Mist
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300-364 Ω
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Delay 1
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3.70-4.10 kΩ
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Delay 2
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2.60-3.20 kΩ
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Delay 3
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1.80-2.20 kΩ
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Delay 4
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1.10-1.50 kΩ
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Delay 5
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650-1000 Ω
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Low
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300-364 Ω
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High
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300-364 Ω
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Windshield Wiper Motor
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1.
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Ignition OFF, disconnect the harness connector at the M75 windshield wiper motor.
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2.
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Install a 25 A fused jumper wire between the control terminal E and 12 V. Install a jumper wire between the ground terminal C and ground.
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3.
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Verify the M75 windshield wiper motor is operating in the low speed mode.
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4.
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If the M75 windshield wiper motor is not in the low speed mode, replace the M75 windshield wiper motor.
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5.
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Install a 25 A fused jumper wire between the control terminal D and 12 V. Install a jumper wire between the ground terminal C and ground.
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6.
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Verify the M75 windshield wiper motor is operating in the high speed mode.
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7.
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If the M75 windshield wiper motor is not in the high speed mode, replace the M75 windshield wiper motor.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
