Schematic Reference: Defogger Schematics

Connector End View Reference: Window Systems Connector End Views

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

1. Turn ON the ignition, with the engine OFF.
2. Press the rear window defogger switch.
3. Observe the rear window defogger indicator on the HVAC control module.

Does the indicator illuminate?

Go to Step 3

Go to Step 8

Connect a test lamp between the rear window defogger grid and a good ground.

Does the test lamp illuminate?

Go to Step 4

Go to Step 5

Connect a test lamp between the left side of the rear window defogger grid and the right side of the rear window defogger grid.

Does the test lamp illuminate?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 10

1. Turn OFF the ignition.
2. Disconnect the harness connector C1 of the liftgate module (LGM)/endgate module (EGM).
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the battery positive voltage circuit, terminal A, of the LGM/EGM and a good ground.

Does the test lamp illuminate?

Go to Step 6

Go to Step 7

Test the supply voltage circuit of the rear window defogger for an open or high resistance. Refer to Circuit Testing and Wiring Repairs.

Did you find and correct the condition?

Go to Step 14

Go to Step 9

Test the battery positive voltage circuit of the LGM/EGM for an open or short to ground. Refer to Circuit Testing and Wiring Repairs.

Did you find and correct the condition?

Go to Step 14

Go to Step 11

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

Did you find and correct the condition?

Go to Step 14

Go to Step 12

Inspect for poor connections at the harness connector of the LGM/EGM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs.

Did you find and correct the condition?

Go to Step 14

Go to Step 13

Repair an open or a high resistance in the ground circuit of the rear window defogger. Refer to Wiring Repairs.

Did you find and correct the condition?

Go to Step 14

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Repair a short to ground in the supply voltage circuit of the rear window defogger. Refer to Wiring Repairs.

Did you find and correct the condition?

Go to Step 14

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Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 14

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Replace the LGM/EGM. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 14

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2