GM Service Manual Online
For 1990-2009 cars only

Test Description

The numbers below refer to the step numbers on the diagnostic table.

  1. The ambient air temperature must be above 3°C (38°F) for this A/C compressor test.

  2. The specified values are from the A/C System Performance Test.

Step

Action

Values

Yes

No

Schematic Reference: HVAC Schematics.

Connector End View Reference: Component Connector End Views.

DEFINITION: The temperature cannot be adjusted, or cooling is insufficient during A/C operation.

1

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle.

2

Important: All DTCs that are set must be diagnosed first unless you were sent to this diagnostic from a specific DTC diagnostic.

  1. Turn ON the ignition, with the engine OFF.
  2. Place the blower motor switch in each speed position.

Does the blower motor operate in any speed position?

--

Go to Step 3

Go to Blower Motor Inoperative.

3

Does the blower motor operate at the desired speeds?

--

Go to Step 4

Go to Blower Motor Malfunction.

4

  1. Start the engine.
  2. Place the mode switch in the face position.
  3. Place the recirculation switch in the ON position.
  4. Observe the recirculation door.
  5. Place the recirculation switch in the OFF position.

Does the recirculation door move from the recirculation position to the outside air position?

--

Go to Step 5

Go to Symptoms - HVAC Systems - Manual

5

Important: The ambient air temperature must be above 3°C (38°F).

  1. Start the engine.
  2. With scan tool, clear any DTCs that are stored in the HVAC control module.
  3. Place the air temperature switch in the coldest position.
  4. Place the mode switch in the bi-level position.
  5. Place the blower motor on high speed.

Does the A/C compressor operate?

--

Go to Step 6

Go to Air Conditioning Compressor Replacement

6

Perform the A/C system performance test. Refer to Air Conditioning (A/C) System Performance Test.

Did you find and correct the condition?

--

Go to Step 8

Go to Step 1

7

Replace the HVAC control module. Refer to Control Module References.

Did you complete the replacement?

--

Go to Step 8

--

8

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2