For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
DEFINITION: Time required to defrost the windshield is longer than usual.
1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to Symptoms - HVAC Systems - Automatic
2 |

1. Start the engine.
2. Select the DEFROST mode.
3. Select the maximum blower speed.

Does sufficient air flow from the defroster outlets?

Go to Step 3

Go to Step 10

3 | Measure the engine operating temperature. Does engine reach normal operating temperature? | Go to Step 4 | Go to Step 8
4 |

1. Select the minimum blower speed.
2. Select the warmest temperature setting.
3. Feel the temperature of the inlet and outlet hoses at the heater core.

Does the inlet heater hose feel warmer than the outlet heater hose?

Go to Step 11

Go to Step 5

5 | Test the operation of the A/C compressor clutch. Does the A/C compressor clutch engage? | Go to Step 7 | Go to Step 6
6 | Repair the A/C compressor clutch. Refer to Air Conditioning Compressor Malfunction . Is the repair complete? | Go to Step 14 | --
7 | Perform the A/C system performance test. Refer to Air Conditioning (A/C) System Performance Test . Is the A/C system operating within the specifications? | Go to Step 9 | Go to Step 12
8 | Repair the low engine temperature concern. Refer to Engine Fails To Reach Normal Operating Temperature . Is the repair complete? | Go to Step 14 |
9 | Inspect for correct operation of the recirculation door. Is the recirculation door operating correctly? | Go to Step 14 | Go to Step 13
10 | Repair the air delivery concern. Refer to DTC B0228, B0413, B0423, B0433, B3779, or B3782 . Is the repair complete? | Go to Step 14 | --
11 | Repair the heating concern. Refer to Heating Performance Diagnostic . Is the repair complete? | Go to Step 14 | --
12 | Repair the A/C performance concern. Refer to Air Conditioning (A/C) System Performance Test . Is the repair complete? | Go to Step 14 | --
13 | Repair the recirculation door concern. Refer to DTC B0228, B0413, B0423, B0433, B3779, or B3782 . Is the repair complete? | Go to Step 14 | --
14 | Operate the system in order to verify the repair. Did you find and correct the condition? | System OK | Go to Step 2