Captiva

Rear Window Defogger Malfunction - C60

When the rear defogger button is pressed, voltage is supplied to the relay coil and the body control module (BCM) also illuminates the rear window defogger indicator. Battery positive voltage is supplied at all times to the relay switched input and the relay coil is always grounded. This allows battery positive voltage from the relay switched input through the switch contacts and out the relay switched output to the rear window demister.

Schematic Reference

Defogger Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Rear Window Defogger Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Ignition ON, observe the operation of the E18 rear window defogger grid and the E49 windshield defogger grid while pressing and depressing the rear defog switch. The E18 rear window defogger grid and the E49 windshield defogger grid should turn ON and OFF each time the switch is pressed and depressed.

⇒	If a single grid is inoperative, refer to Single Defogger Grid Inoperative.

⇒	If both grids are always ON or always OFF, refer to Window Defogger System Malfunction.

2. Observe the function of the defogger indicator while pressing and depressing the rear defog switch, the defogger indicator should turn ON and OFF each time the switch is pressed and depressed.

⇒	If the defogger indicator is always ON or always OFF, refer to Defogger Indicator Malfunction.

Single Defogger Grid Inoperative

1. Ignition OFF, disconnect the harness connectors at the appropriate E18 rear window defogger grid or the E49 windshield defogger grid.
2. Test for less than 10 Ω between the ground circuit terminal listed below and ground:

•	Ground terminal 1 for the E18 rear window defogger grid.

•	Ground terminal 2 for the E49 windshield defogger grid.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, connect a test light between the control circuit terminal 1 and ground.
4. Command the defogger grid ON and OFF by pressing and depressing the rear defog switch. The test lamp should turn ON and OFF each time the switch is pressed.

⇒	If the test lamp is always OFF and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the defogger grid.

⇒	If the test lamp is always OFF and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, replace the X50A fuse block-underhood.

5. If all circuits test normal, replace the X50A fuse block-underhood.

Window Defogger System Malfunction

1. Ignition OFF, disconnect the KR5 rear defogger relay.
2. Test for less than 10 Ω between the ground circuit terminal 86 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.

⇒	If the test lamp illuminates, test the control circuit for a short to voltage.

4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.

⇒	If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

5. Connect a 30 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the E18 rear window defogger grid and the E49 windshield defogger grid is activated.

⇒	If the window defogger grids do 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 appropriate defogger grid.

6. Connect a test lamp between the control circuit terminal 85 and the ground circuit terminal 86.
7. Command the defogger grids ON and OFF pressing and depressing the rear defog switch. The test lamp should turn ON and OFF when changing between the commanded states.

⇒	If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, refer to HVAC Control Module Test.

⇒	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, refer to HVAC Control Module Test.

8. If all circuits test normal, test or replace the KR5 rear defogger relay.

HVAC Control Module Test

1. Ignition OFF, disconnect the X2 harness connector at the K33 HVAC control module.
2. Test for less than 10 Ω between the ground circuit terminal 17 and ground.

⇒	If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, test for greater than 10 V between the signal circuit terminal 4 and ground.

⇒	If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.

4. If all circuits test normal, replace the K33 HVAC control module.

Rear Defog Indicator Malfunction

1. Ignition OFF, disconnect the X2 harness connector at the K9 BCM.
2. Ignition ON, verify that the defogger indicator is OFF.

⇒	If the defogger indicator is ON, test the control circuit terminal 6 for a short to voltage. If the circuit tests normal, replace the K33 HVAC control module.

3. Connect a 3 A fused jumper wire between the control circuit terminal 6 and B+, verify that the defogger indicator is ON.

⇒	If the defogger indicator is OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K33 HVAC control module.

4. If all circuits test normal, replace the K9 BCM.

Rear Window Demister Grid Test

1. Ignition ON, turn on the rear window demister.
2. Verify that a test lamp illuminates between each rear window demister grid line and ground. The test lamp should be off when testing at the ground side of the grid and get brighter as the test lamp moves closer to the voltage supply side of the grid. The test lamp should be dim when testing each grid line in the middle.

⇒	If the test lamp remains bright at the middle of the grid line, test for an open between the test point and the ground side of the grid.

⇒	If the test lamp remains off at the middle of the grid line, test for an open between the test point and the voltage supply side of the grid.

Defog Switch

1. Ignition OFF, disconnect the X2 harness connector at the K33 HVAC control module.
2. Test for infinite resistance between the signal terminal 4 and the ground terminal 17 with the switch in the open position.

⇒	If not the specified value, replace the K33 HVAC control module.

3. Test for less than 2 ohms between the signal terminal 4 and the ground terminal 17 with the switch in the closed position.

⇒	If greater than the specified range, replace the K33 HVAC control module.

Defog Indicator

1. Ignition OFF, disconnect the X2 harness connector at the K33 HVAC control module.
2. Install a 5 A fused jumper wire between the control terminal 5 and 12 V. Install a jumper wire between the ground terminal 17 and ground. Verify the defog indicator illuminates.

⇒	If the defog indicator does not illuminate, replace the K33 HVAC control module.

Relay Test

1. Ignition OFF, disconnect the KR5 rear defogger relay.
2. Test for 60-180 Ω between terminals 85 and 86.

⇒	If not within the specified range, replace the KR5 rear defogger relay.

3. Test for infinite resistance between the following terminals:

•

30 and 86

•

30 and 87

•

30 and 85

•

85 and 87

⇒	If not the specified value, replace the KR5 rear defogger relay.

4. Install a 5 A fused jumper wire between relay terminal 85 and 12 V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 Ω between terminals 30 and 87.

⇒	If greater than the specified range, replace the KR5 rear defogger relay.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.