The numbers below refer to the step numbers on the diagnostic table.
If Load Shed Lvl.2 R. Defog. data parameter is displayed as Enabled, system voltage may be low due to number of loads enabled on the vehicle, while the ignition is ON. This may be normal due to the number of loads enabled or the vehicle may have a charging system or battery concern.
Gain access to the RR DEFOG relay and listen for an audible click when the relay operates. Command both the ON and OFF states of the RR DEFOG relay. Repeat the commands as necessary.
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 |
Does the rear window defogger indicator illuminate? | Go to Step 3 | Go to Step 5 |
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 7 |
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 17 |
5 | With a scan tool, observe the Rear Defog Relay data parameter in the rear integration module (RIM) data list. Does the scan tool display ON? | Go to Step 6 | Go to Step 14 |
With a scan tool, observe the Load Shed Lvl. 2 R. Defog. data parameter in the RIM data list. Does the scan tool display Enabled? | Go to Step 14 | ||
Do you hear a click when you command the RR DEFOG relay ON and OFF? | Go to Step 10 | Go to Step 8 | |
8 |
Does the test lamp illuminate? | Go to Step 9 | Go to Step 18 |
9 |
Does the test lamp illuminate? | Go to Step 15 | Go to Step 12 |
10 |
Does the test lamp illuminate? | Go to Step 11 | Go to Step 13 |
11 |
Does the test lamp illuminate? | Go to Step 15 | Go to Step 20 |
12 | Test the control circuit of the RR 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 24 | Go to Step 16 |
13 | Test the battery positive voltage circuit of the RR DEFOG relay switched input for an open or high resistance. Refer to Circuit Testing and Wiring Repairs. Did you find and correct the condition? | Go to Step 24 | Go to Step 19 |
14 | 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 24 | Go to Step 21 |
15 | Inspect for a poor connection at the RR DEFOG relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | Go to Step 24 | Go to Step 22 |
16 | Inspect for a poor connection at the harness connector of the RIM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs. Did you find and correct the condition? | Go to Step 24 | Go to Step 23 |
17 | Repair an open or high resistance in the ground circuit of the rear window defogger. Refer to Wiring Repairs. Did you complete the repair? | Go to Step 24 | -- |
18 | Repair an open or a high resistance in the ignition voltage circuit of the RR DEFOG relay coil. Refer to Wiring Repairs. Did you complete the repair? | Go to Step 24 | -- |
19 | Repair a short to ground in the supply voltage circuit of the rear window defogger. Refer to Wiring Repairs. Did you complete the repair? | Go to Step 24 | -- |
20 | Repair an open or high resistance in the supply voltage circuit of the rear window defogger. Refer to Wiring Repairs. Did you complete the repair? | Go to Step 24 | -- |
21 | Replace the HVAC control module. Refer to HVAC Control Module Replacement. Did you complete the replacement? | Go to Step 24 | -- |
22 | Replace the RR DEFOG relay. Refer to Relay Replacement. Did you complete the replacement? | Go to Step 24 | -- |
23 | Replace the RIM. Refer to Control Module References for replacement, setup, and programming. Did you complete the replacement? | Go to Step 24 | -- |
24 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 2 |