Too Hot in Vehicle. Buick Regal (China) 2001

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 18

Go to Step 8

Turn ON the ignition, with the engine OFF.
Observe the left and right air temperature actuator drive shaft.
Place the air temperature switch from the coldest position to the warmest position.

Does the air temperature actuator drive shaft rotate at all?

Go to Step 9

Go to Step 10

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

•	Misaligned left or right air temperature actuator. Refer to Air Temperature Actuator Replacement - Left Side and Air Temperature Actuator Replacement - Right Side .

•	Broken or binding linkages or air temperature door

•	An obstruction that prevents the air temperature door from operating within it's full range of motion

•	Missing seals to the air temperature door

•	Misaligned seals to the air temperature door

Did you find and correct the condition?

Go to Step 18

Go to Step 10

Test the ignition-3 voltage circuit of the suspect 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 18

Go to Step 11

Test the ground circuit of the suspect 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 18

Go to Step 12

Test the suspect air temperature door position 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 18

Go to Step 13

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

Turn ON the ignition, with the engine OFF.
Measure the voltage from the suspect air temperature door position signal circuit of the suspect air temperature actuator to a good ground.
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?

0-12 V

Go to Step 15

Go to Step 14

Inspect for poor connections at the harness connector of the suspect 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 18

Go to Step 16

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 18

Go to Step 17

Replace the suspect air temperature actuator. Refer to Air Temperature Actuator Replacement - Left Side or Air Temperature Actuator Replacement - Right Side .

Did you complete the replacement?

Go to Step 18

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

Did you complete the replacement?

Go to Step 18

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2

Too Hot in Vehicle CJ4

Test Description

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

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

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

Schematic Reference: HVAC Schematics

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

Did you perform the HVAC Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

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

Does the blower motor operate in any of the speed positions?

Go to Step 3

Go to Blower Motor Inoperative

Does the blower motor operate at the desired speeds?

Go to Step 4

Go to Blower Motor Malfunction

When the A/C is ON, does the customer concern occur?

Go to Step 5

Go to Step 7

Start the engine.
Place the blower motor switch in the maximum speed position.
Place the recirculation switch in the recirculation position.

Does the recirculation door move to the recirculation position?

Go to Step 6

Go to Air Recirculation Malfunction

Place the blower motor switch in the maximum speed position.
Place the mode switch in the bi-level position.
Place the air temperature switch in the coldest position.

Does the A/C compressor operate?

Go to Step 7

Go to HVAC Compressor Clutch Does Not Engage

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 24

Go to Step 8

Observe the air temperature actuator drive shaft.
Place the air temperature switch from the coldest position to the warmest position.

Does the air temperature actuator drive shaft rotate at all?

Go to Step 9

Go to Step 10

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 it's full range of motion

•	Missing seals to the air temperature door

•	Misaligned seals to the air temperature door

Did you find and correct the condition?

Go to Step 24

Go to Step 14

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 24

Go to Step 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 24

Go to Step 12

Test the air temperature door position 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 24

Go to Step 13

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

Turn ON the ignition, with the engine OFF.
Measure the voltage from the air temperature door position signal circuit of the air temperature actuator to a good ground.
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?

0-12 V

Go to Step 20

Go to Step 21

Disconnect the HVAC control module .
Turn ON the ignition, with the engine OFF.
Measure the voltage from the ignition-3 voltage circuit of the HVAC control module to the ground circuit of the HVAC control module .

Does the voltage measure greater than specified value?

12 V

Go to Step 16

Go to Step 15

Measure the voltage from the ignition-3 voltage circuit of the HVAC control module to a good ground.

Does the voltage measure greater than specified value?

12 V

Go to Step 17

Go to Step 18

Measure the voltage from the battery positive voltage circuit of the HVAC control module to a good ground.

Does the voltage measure greater than specified value?

12 V

Go to Step 21

Go to Step 19

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

Did you find and correct the condition?

Go to Step 19

Go to Step 21

Test the ignition-3 circuit of the HVAC control module for short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 21

Test the battery positive voltage circuit of the HVAC control module for short to ground, a high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 24

Go to Step 21

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 24

Go to Step 22

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

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

Did you complete the replacement?

Go to Step 24

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

Did you complete the replacement?

Go to Step 24

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2