For 1990-2009 cars

### Test Description

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

1. The ambient air temperature must be above 4°C (40°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: HVAC Connector End Views DEFINITION: The temperature cannot be adjusted, or cooling is insufficient during A/C operation.
1 | Did you perform the HVAC Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - HVAC Systems - Automatic
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 panel 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 Air Recirculation Malfunction

5 | Does the customer concern occur when the air conditioning is ON? | -- | Go to Step 6 | Go to Step 8
6 | Important: The ambient air temperature must be above 4°C (40°F).

1. Start the engine.
2. Place the air temperature switch in the coldest position.
3. Place the mode switch in the bi-level position.
4. Place the A/C request switch to the ON position.

Does the A/C compressor operate?

--

Go to Step 7

Go to HVAC Compressor Clutch Does Not Engage

7 | Perform the A/C system performance test. Refer to Air Conditioning (A/C) System Performance Test in Heating, Ventilation, and Air Conditioning. Did you find and correct the condition? | -- | Go to Step 24 | Go to Step 8
8 | Inspect the inside air temperature sensor for proper installation. Refer to HVAC Control Module Replacement . Did you find and correct the condition? | -- | Go to Step 24 | Go to Step 9
9 |

1. Turn the ignition ON, with the engine OFF.
2. Place the mode switch in panel position.
3. Place the blower motor switch in maximum speed position.
4. Inspect for airflow through the inside air temperature sensor by placing a 5 cm (2 in) square piece of paper over the sensor air inlet.

Does the paper stay in place?

--

Go to Step 10

Go to Step 16

10 |

1. Install a thermometer near the inside air temperature sensor.
2. With a scan tool, observe the Inside Air Temp parameter in the General Info-Outputs data list.

Does the scan tool indicate the sensor temperatures is within 3°C (5°F) of the thermometer temperature?

--

Go to Step 11

Go to Step 14

11 |

1. Turn the ignition OFF.
2. Cover the ambient light sensor.
3. Start the engine.
4. Adjust temperature to 22°C (72°F).
5. With a scan tool, observe the Solar Sensor parameter in the Defrost data list.

Is the Solar Sensor parameter greater than the specified value?

220 counts

Go to Step 12

Go to Step 18

12 |

1. Uncover the ambient light sensor.
2. Direct a light source at the ambient light sensor.
3. Observe the Solar Sensor parameter in the Defrost data list.

Do the counts change?

--

Go to Step 13

Go to Step 18

13 | Test the resistance of the ambient air temperature sensor. Refer to Temperature Versus Resistance in Engine Controls - 3.0L or Temperature Versus Resistance in Engine Controls - 2.2L. Is the resistance near the value in the temperature vs resistance table? | -- | Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems | Go to Step 15
14 | Test the resistance of the inside air temperature sensor. Refer to Temperature Versus Resistance in Engine Controls - 3.0L or Temperature Versus Resistance in Engine Controls - 2.2L. Is the resistance near the value in the temperature vs resistance table? | -- | Go to Step 19 | Go to Step 17
15 | Inspect for poor connections at the harness connector of the ambient air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 24 | Go to Step 22
16 | Inspect the aspirator tube for a air leak or obstruction. Did you find and correct the condition? | -- | Go to Step 24 | --
17 | Inspect for poor connections at the harness connector of the inside air temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 24 | Go to Step 20
18 | Inspect for poor connections at the harness connector of the ambient light sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 24 | Go to Step 21
19 | Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 24 | Go to Step 23
20 | Replace the inside air temperature sensor. Refer to HVAC Control Module Replacement . Did you complete the replacement? | -- | Go to Step 24 | --
21 | Replace the ambient light sensor. Refer to Ambient Light Sensor Replacement in Lighting Systems. Did you complete the replacement? | -- | Go to Step 24 | --
22 | Replace the ambient air temperature sensor. Refer to Ambient Air Temperature Sensor Replacement . Did you complete the replacement? | -- | Go to Step 24 | --
23 | Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement? | -- | Go to Step 24 | --
24 | Operate the system in order to verify the repair. Did you correct the condition? | -- | System OK | Go to Step 2