GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Pontiac 🢒 2005 🢒 Grand Am 🢒 HVAC 🢒 HVAC Systems - Manual 🢒 Too Hot in Vehicle

Test Description

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

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

    2.

  2. The voltage will vary between 0-12 volts during normal operation. The HVAC control module connector must be connected during this step.

Step

Action

Values

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The temperature cannot be adjusted, or the 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 in Vehicle DTC Information

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

Does the blower motor operate at all?

--

Go to Step 3

Go to Blower Motor Inoperative

3

Does the blower motor operate correctly, provide sufficient airflow, for each speed position?

--

Go to Step 4

Go to Blower Motor Malfunction

4
  1. Place the mode switch in the vent position.
  2. Place the blower motor switch in the maximum speed position.
  3. Place the outside air switch in the ON position.
  4. Place the recirculation switch in the ON position.

Does the recirculation door operate properly?

--

Go to Step 5

Go to Air Recirculation Malfunction

5

Does the Too Hot in Vehicle concern occur when A/C cooling is desired?

--

Go to Step 6

Go to Step 8

6

Important: For A/C compressor operation, ambient air temperature must be above 3°C (38°F).

  1. Start the engine.
  2. Place the blower motor switch in the maximum speed position.
  3. Place the mode switch in the vent position.
  4. Place the temperature switch in the coldest position.

Does the A/C compressor operate?

--

Go to Step 7

Go to HVAC Compressor Clutch Does Not Engage

7

Perform the refrigerant 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 21

Go to Step 8

8
  1. Observe the air temperature actuator drive shaft.
  2. Adjust the air temperature switch.

Does the air temperature actuator drive shaft rotate at all?

--

Go to Step 9

Go to Step 10

9

Inspect the air temperature door and the air temperature actuator for the following conditions:

    • A misaligned air temperature actuator--Refer to Air Temperature Actuator Replacement .
    • Broken or binding linkages or air temperature door
    • An obstruction that prevents the air temperature door from operating within its full range of motion
    • Missing seals on the air temperature door
    • Misaligned seals on the air temperature door

Did you find and correct the condition?

--

Go to Step 21

Go to Step 10

10

Test the ignition 3 voltage circuit of the air temperature actuator for an open or a high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 11

11

Test the ground circuit of the air temperature actuator for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 12

12

Test the air temperature door control signal circuit of the air temperature actuator for an open, high resistance, short to ground, or short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 13

13

Test the ignition 3 voltage circuit of the HVAC control assembly for an open or a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 14

14

Test the ground circuit of the HVAC control assembly for an open or a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 15

15

Important: Ensure that the HVAC control assembly connector is connected during this step in order to avoid misdiagnosis.

  1. Turn ON the ignition, with the engine OFF.
  2. Measure the voltage from the air temperature door control signal circuit of the air temperature actuator to a good ground.
  3. Place the air temperature switch from the coldest position to the warmest position.

Does the voltage measure within the specified values with a smooth transition between cold and hot?

12 V at cold, 0 V at hot

Go to Step 17

Go to Step 16

16

Inspect for poor connections at the harness connector of the air temperature actuator. 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 21

Go to Step 17

17

Inspect the air temperature actuator, door, and any attaching linkage for binding or a condition that prevents drive shaft rotation.

Did you find and correct the condition?

--

Go to Step 21

Go to Step 19

18

Inspect for poor connections at the harness connector of the HVAC control assembly. 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 21

Go to Step 20

19

Replace the air temperature actuator. Refer to Air Temperature Actuator Replacement .

Did you complete the replacement?

--

Go to Step 21

--

20

Replace the HVAC control assembly. Refer to Heater and Air Conditioning Control Replacement .

Did you complete the replacement?

--

Go to Step 21

--

21

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2