For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
DEFINITION: Time required to defrost the windshield is longer than normal.
1 | Were you sent here from Symptoms or another diagnostic table? | Go to Step 2 | Go to Symptoms - HVAC Systems - Manual or 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 a normal operating temperature? | Go to Step 4 | Go to Step 8
4 |

1. Select the minimum blower speed.
2. Select the maximum temperature setting.

Warning: Refer to Moving Parts and Hot Surfaces Warning in the Preface section.

3. Feel the temperature of the inlet and outlet hoses at the heater core.

Does the inlet hose feel warmer than the outlet 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. Check for obstructions in the ducts. 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 Symptoms - HVAC Systems - Manual for the manual systems or Symptoms - HVAC Systems - Automatic for the automatic systems. Is the repair complete? | Go to Step 14 | --
13 | Repair the recirculation door concern. Check the cabin air filter and duct for an obstruction. Is the repair complete? | Go to Step 14 | --
14 | Operate the system in order to verify the repair. Did you find and correct the problem? | System OK | Go to Step 2