GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2006 🢒 STS 🢒 HVAC 🢒 Heating, Ventilation and Air Conditioning 🢒 Too Hot in Vehicle

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.

  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 Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

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 Malfunction

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 3°C (38°F).

  1. Start the engine.
  2. Place the left 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 .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 8

8

Inspect the inside air temperature sensor for proper installation. Refer to Inside Air Temperature Sensor Replacement .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 9

9
  1. Turn ON the ignition 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 Climate Control Panel 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 OFF the ignition.
  2. Cover the sunload sensor.
  3. Start the engine.
  4. Adjust driver side temperature to 22°C (72°F).
  5. With a scan tool, observe the Driver and Passenger Solar Sensor parameter in the Climate Control Panel Open/Short data list.

Is the Solar Sensor parameter greater than the specified value?

220 Counts

Go to Step 12

Go to Step 19

12
  1. Uncover the sunload sensor.
  2. Direct a light source at the sunload sensor.
  3. Observe the Driver and Passenger Sunload parameter.

Do the counts change?

--

Go to Step 13

Go to Step 19

13

Test the resistance of the ambient air temperature sensor. Refer to Sensor Resistance Table .

Is the resistance near the value in the Sensor Resistance Table?

--

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 15

14

Test the resistance of the inside air temperature sensor. Refer to Sensor Resistance Table .

Is the resistance near the value in the Sensor Resistance Table?

--

Go to Step 20

Go to Step 18

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 .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 17

16

Inspect the aspirator tube for a air leak or obstruction.

Did you find and correct the condition?

--

Go to Step 25

--

17

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 .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 23

18

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 .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 21

19

Inspect for poor connections at the harness connector of the sunload sensor. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 22

20

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 .

Did you find and correct the condition?

--

Go to Step 25

Go to Step 24

21

Replace the inside air temperature sensor. Refer to Inside Air Temperature Sensor Replacement .

Did you complete the replacement?

--

Go to Step 25

--

22

Replace the sunload sensor. Refer to Sun Load Sensor Replacement .

Did you complete the replacement?

--

Go to Step 25

--

23

Replace the ambient air temperature sensor. Refer to Ambient Air Temperature Sensor Replacement .

Did you complete the replacement?

--

Go to Step 25

--

24

Replace the HVAC control module. Refer to Control Module References for replacement, setup, and programming.

Did you complete the replacement?

--

Go to Step 25

--

25

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2