DEFINITION: Time required to defrost the windshield is longer than normal.

Were you sent here from Symptoms or another diagnostic table?

Go to Step 2

Go to Symptoms - HVAC Systems - Manual or Symptoms - HVAC Systems - Automatic

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 8

Measure the engine operating temperature.

Does engine reach a normal operating temperature?

Go to Step 4

Go to Step 6

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 9

Go to Step 5

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 7

Go to Step 10

Repair the low engine temperature concern. Refer to Engine Fails To Reach Normal Operating Temperature .

Is the repair complete?

Go to Step 12

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Inspect for correct operation of the air inlet valve.

Is the air inlet valve operating correctly?

Go to Step 12

Go to Step 11

Repair the air delivery concern. Refer to Air Delivery Improper .

Is the repair complete?

Go to Step 12

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Repair the heating concern. Refer to Heating Performance Diagnostic .

Is the repair complete?

Go to Step 12

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Repair the A/C performance concern. Refer to Symptoms - HVAC Systems - Manual or Symptoms - HVAC Systems - Automatic .

Is the repair complete?

Go to Step 12

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Repair the air inlet valve concern. Refer to Air Recirculation Malfunction .

Is the repair complete?

Go to Step 12

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Operate the system in order to verify the repair.

Did you find and correct the problem?

System OK

Go to Step 2