The number below refers to the step number on the diagnostic table.
Step | Action | Yes | No |
---|---|---|---|
Schematic Reference: Defogger Schematics Connector End View Reference: Window Systems Connector End Views | |||
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | |
2 |
Important: Make sure that the park or head lights are turned OFF. The backlighting will effect the illumination of the rear window defogger indicator.
Does the rear window defogger indicator illuminate? | Go to Step 3 | Go to Step 12 |
3 | Connect a test lamp between the rear window defogger grid and ground. Does the test lamp illuminate? | Go to Step 4 | Go to Step 5 |
4 | 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 19 |
Command the REAR DEFOG relay ON and OFF, by depressing the rear defogger switch on the HVAC control module. Do you hear a click when you command the REAR DEFOG relay ON and OFF? | Go to Step 8 | Go to Step 6 | |
6 |
Does the test lamp illuminate? | Go to Step 7 | Go to Step 11 |
7 |
Does the test lamp illuminate? | Go to Step 17 | Go to Step 12 |
8 |
Does the test lamp illuminate? | Go to Step 9 | Go to Step 13 |
9 |
Does the test lamp illuminate? | Go to Step 17 | Go to Step 10 |
10 |
Does the test lamp illuminate? | Go to Step 14 | Go to Step 21 |
11 | Test the supply voltage circuit of the REAR DEFOG relay coil for an open or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 26 | Go to Step 16 |
12 | Test the control circuit of the REAR DEFOG relay for an open or short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 26 | Go to Step 15 |
13 | Test the battery positive voltage circuit of the REAR DEFOG relay switched input for an open or short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 26 | Go to Step 20 |
14 | Test the supply voltage circuit of the rear window defogger grid between the radio antenna module and the rear window defogger grid for an open or high resistance. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 26 | Go to Step 18 |
15 | 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 . Did you find and correct the condition? | Go to Step 26 | Go to Step 22 |
16 | 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 . Did you find and correct the condition? | Go to Step 26 | Go to Step 23 |
17 | Inspect for a poor connection at the REAR DEFOG relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 26 | Go to Step 24 |
18 | Inspect for a poor connection at the harness connector of the radio antenna module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 26 | Go to Step 25 |
19 | Repair an open or high resistance in the ground circuit of the rear window defogger grid. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 26 | -- |
20 | Repair the short to ground in the supply voltage circuit of the rear window defogger grid. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 26 | -- |
21 | Repair an open or high resistance in the supply voltage circuit of the rear window defogger grid. Refer to Wiring Repairs . Did you complete the repair? | Go to Step 26 | -- |
22 | Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 26 | -- |
23 | Replace the BCM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 26 | -- |
24 | Replace the REAR DEFOG relay. Refer to Relay Replacement . Did you complete the replacement? | Go to Step 26 | -- |
25 | Replace the radio antenna module. Refer to Radio Antenna Module Replacement . Did you complete the replacement? | Go to Step 26 | -- |
26 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |