Schematic Reference: Defogger Schematics

Connector End View Reference: Stationary Windows Connector End Views

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

Important: Make sure that system voltage is near normal operating range on the vehicle. This will effect the illumination of the rear window defogger indicator.

1. Turn ON the ignition, with the engine OFF.
2. Depress the rear defogger switch.
3. Observe the defogger on indicator.

Does the defogger on indicator illuminate?

Go to Step 3

Go to Step 8

1. Turn OFF the ignition.
2. Remove the rear defog relay.
3. Connect a test lamp between the rear defog relay control circuit and battery positive voltage circuit of the relay connector.
4. Turn ON the ignition, with the engine OFF.
5. Using a scan tool, command the rear defog relay ON and OFF.

Does the test lamp illuminate as expected?

Go to Step 4

Go to Step 7

4

1. Turn OFF the ignition.
2. Install the rear defog relay.
3. Turn ON the ignition, with the engine OFF.
4. Using a scan tool, command the rear defog relay ON and OFF.

Does the rear defog relay click as expected?

Go to Step 5

Go to Step 6

Test for an open or high resistance in the ground circuit of the rear window defogger grid. Refer to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 9

Inspect for a poor connection at the RR defog relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 10

Inspect for a poor connection at the harness connector of the body control module (BCM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 11

Inspect for a poor connection at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 13

Go to Step 12

Repair an open or high resistance in the rear defog element supply voltage circuit of the RR defog relay. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 13

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Replace the RR defog relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 13

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Replace the BCM. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 13

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Replace the HVAC control module. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 13

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Important: If the ignition key was placed in the ON position with the rear defog relay removed a DTC B0283 may have set. Ensure no DTC has set or use a scan tool to clear DTC.

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2