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 10

Measure the engine operating temperature.

Does engine reach a normal operating temperature?

Go to Step 10

Go to Step 8

1. Select the minimum blower speed.
2. Select the warmest 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 heater hose feel warmer than the outlet heater hose?

Go to Step 11

Go to Step 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

Repair the A/C compressor clutch. Refer to Air Conditioning Compressor Malfunction for automatic systems or Air Conditioning Compressor Malfunction for manual systems.

Is the repair complete?

Go to Step 14

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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

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

Is the repair complete?

Go to Step 14

--

Inspect for correct operation of the recirculation door.

Is the recirculation door operating correctly?

Go to Step 14

Go to Step 13

Repair the air delivery concern. Refer to DTC B0228, B0413, B0423, B0433, B3779, or B3782 for automatic systems or DTC B0413, B0423, B0433, B3779, or B3782 for manual systems.

Is the repair complete?

Go to Step 14

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Repair the heating concern. Refer to Heating Performance Diagnostic.

Is the repair complete?

Go to Step 14

--

Repair the A/C performance concern. Refer to Air Conditioning (A/C) System Performance Test.

Is the repair complete?

Go to Step 14

--

Repair the recirculation door concern. Refer to DTC B0228, B0413, B0423, B0433, B3779, or B3782 for automatic systems or DTC B0413, B0423, B0433, B3779, or B3782 for manual systems.

Is the repair complete?

Go to Step 14

--

Operate the system in order to verify the repair.

Did you find and correct the condition?

System OK

Go to Step 2