Rear Wiper System Malfunction
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Rear 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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Rear Wiper Switch Signal
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2
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1
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1
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-
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Rear Window Wiper Control
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1
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1
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2
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-
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Rear Window Wiper Relay Control
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B370B 02
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1
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2
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-
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Rear Window Wiper Ground
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-
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1
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1
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-
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1. Wiper Inoperative
2. Wiper Always ON
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Circuit/System Description
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The body control module (BCM) controls the dual speed rear wiper motor by its active high output to the external rear wiper motor relay. When the BCM activates its output and applies battery to the coil of the relay, the relay energizes, allowing battery voltage from the fuse to be applied through the switched contacts of the rear wiper motor relay to the control input of the rear wiper motor . The motor operates continuously at low speed when the rear wiper switch is set to the continuous or delay setting. The rear motor internally controls if the rear wipers are in the low or delay setting.
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 diagnostic tester information.
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Circuit/System Verification
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Verify the Rear Wiper Command parament is active when operating the rear wipers.
Rear Wiper/Washer Switch Circuit Malfunction
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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 that a test lamp illuminates between the low reference 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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Test for 10 V between the signal circuit terminal 4 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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If all circuits test normal, replace the S82 windshield wiper/washer switch.
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Rear Wiper Motor Circuit Malfunction
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1.
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Ignition OFF, disconnect the KR7 rear wiper relay.
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2.
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Test for less than 5 Ω between the ground circuit terminal 86 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 the ground circuit for an open/high resistance.
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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 the rear wiper fuse for an open. If the fuse is open, test the control circuit terminal 30 for a short to ground.
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8.
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Verify that a test lamp does not illuminate between the control circuit terminal 30 and ground.
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9.
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If the test lamp illuminates, test the control circuit for a short to voltage.
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10.
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Connect a test lamp between the control cirucit terminal 85 and ground.
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11.
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Command the rear wiper ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.
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12.
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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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13.
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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 K9 BCM.
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14.
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Ignition OFF, disconnect the connector at the M45 rear wiper motor.
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15.
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Test for less than 5 Ω between the ground circuit terminal C and ground.
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16.
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If greater than the specified range, test the ground circuit for an open/high resistance.
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17.
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Ignition ON, verify a test lamp illuminates between B+ circuit terminal B and ground.
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18.
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If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
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19.
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Connect the harness connector at the M45 rear wiper motor.
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20.
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Connect a 3 A fused jumper wire between the control circuit terminal 30 and B+. Verify the rear wiper motor is activated.
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21.
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If the rear wiper motor does not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the M45 rear wiper motor.
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22.
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If all circuits test normal, test or replace the KR7 Rear Wiper Relay.
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Relay Test
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1.
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Ignition OFF, connect the KR7 rear wiper relay.
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2.
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Test for 60-200 Ω between terminals 85 and 86.
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3.
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If the resistance is not within the specified range, replace the KR7 rear wiper relay.
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4.
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Test for infinite resistance between the following terminals:
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5.
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If not the specified value, replace the KR7 rear wiper relay.
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6.
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Test for less than 5 Ω between terminals 30 and 87A.
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7.
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If greater than the specified range, replace the KR7 rear wiper relay.
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8.
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Install a 10 A fused jumper wire between relay terminal 85 and B+. Install a jumper wire between relay terminal 86 and ground. Test for less than 5 Ω between terminals 30 and 87.
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9.
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If greater than the specified range, replace the KR7 rear wiper relay.
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Rear Wiper Motor Test
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1.
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Ignition OFF, disconnect the harness connector at the M45 rear wiper motor.
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2.
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Install a 25 A fused jumper wire between the B+ terminal A 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 M45 rear wiper motor is operating.
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4.
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If the M45 rear wiper motor is not operating, replace the M45 rear wiper motor.
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Perform the
Diagnostic Repair Verification
after completing the diagnostic procedure.
