Schematic Reference: Defogger Schematics

Component End View Reference: Stationary Windows Connector End Views

Did you perform the Defogger Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Defogger

1. Turn ON the ignition, with the engine OFF.
2. Operate the HVAC controls on the HVAC Control Module.

Does the HVAC system operate normally?

Go to Step 3

Go to Diagnostic System Check - HVAC Systems - Automatic in HVAC Systems - Automatic

1. Depress the rear window defogger switch.
2. Observe the rear window defogger indicator on the HVAC Control Module.

Does the rear window defogger indicator illuminate?

Go to Step 4

Go to Step 16

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

Does the test lamp illuminate?

Go to Step 5

Go to Step 6

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 in Wiring Systems

Go to Step 12

6

1. Using a scan tool, select from the special functions, the Rear Defogger from the Body Control Module (BCM) output controls.
2. With a scan tool, command the rear HTD BK LITE relay ON and OFF.

Do you hear a click when you command the HTD BK LITE relay ON and OFF?

Go to Step 9

Go to Step 7

1. Turn OFF the ignition.
2. Disconnect the HTD BK LITE relay.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the ignition voltage circuit of the HTD BK LITE relay coil and ground.

Does the test lamp illuminate?

Go to Step 8

Go to Step 21

1. Connect a test lamp between the control circuit of the HTD BK LITE relay and the ignition voltage circuit of the HTD BK LITE relay coil.
2. With a scan tool, command the HTD BK LITE relay ON.

Does the test lamp illuminate?

Go to Step 18

Go to Step 13

1. Turn OFF the ignition.
2. Disconnect the HTD BK LITE relay.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the battery positive voltage circuit of the HTD BK LITE relay switched input and a good ground.

Does the test lamp illuminate?

Go to Step 10

Go to Step 14

1. Connect a 40 amp fused jumper between the battery positive voltage circuit of the HTD BK LITE relay switched input and the relay switched output to the supply voltage circuit of the rear window defogger.
2. Connect a test lamp between the rear window defogger grid and a good ground.

Does the test lamp illuminate?

Go to Step 18

Go to Step 11

1. Turn OFF the ignition.
2. Disconnect the Radio Antenna Module.
3. Turn ON the ignition, with the engine OFF.
4. Connect a test lamp between the supply voltage circuit of the rear window defogger and ground.

Does the test lamp illuminate?

Go to Step 15

Go to Step 23

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

Did you find and correct the condition?

Go to Step 29

Go to Step 17

Test the control circuit of the HTD BK LITE relay for an open or short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 19

Test the battery positive voltage circuit of the HTD BK LITE relay switched input for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 22

Test the supply voltage circuit of the rear window defogger between the harness connector of the Radio Antenna Module and the rear window defogger for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 20

Inspect for poor connections 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 29

Go to Step 24

Inspect for poor connections at the Radio Antenna Module Coil. 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 29

Go to Step 25

Inspect for poor connections at the HTD BK LITE 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 29

Go to Step 26

Inspect for poor connections at the harness connector of the 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 29

Go to Step 27

Inspect for poor connections at the Radio Antenna 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 29

Go to Step 28

Repair an open or a high resistance in the ignition voltage circuit of the HTD BK LITE relay coil. Refer to Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

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

Did you complete the repair?

Go to Step 29

--

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

Did you complete the repair?

Go to Step 29

--

Replace the HVAC Control Module. Refer to HVAC Control Module Replacement in HVAC Systems - Automatic.

Did you complete the replacement?

Go to Step 29

--

Replace the Radio Antenna Module Coil. Refer to Antenna Module Coil Replacement in Entertainment.

Did you complete the replacement?

Go to Step 29

--

Replace the HTD BK LITE relay. Refer to Relay Replacement in Wiring Systems.

Did you complete the replacement?

Go to Step 29

--

Important: Perform the setup procedure for the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration in Body Control System.

Replace the BCM. Refer to Body Control Module Replacement in Body Control System.

Did you complete the replacement?

Go to Step 29

--

Replace the Radio Antenna Module. Refer to Radio Antenna Module Replacement in Entertainment.

Did you complete the replacement?

Go to Step 29

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2