GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 2007 🢒 Uplander 🢒 HVAC 🢒 HVAC - Manual 🢒 Too Hot in Vehicle

Test Description

The number below refers to the step number on the diagnostic table.

  1. 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

Important: Both the left and the right air temperature controls are diagnosed in this table.

Did you perform the Diagnostic System Check - Vehicle?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle

2
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the DTC List in Vehicle DTC Information.

Does the scan tool display any DTC B0408, B0409, B0414, B0418, B0419, or B0424?

--

Go to Diagnostic Trouble Code (DTC) List - Vehicle

Go to Step 3

3
  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 of the speed positions?

--

Go to Step 4

Go to Blower Motor Inoperative

4

Does the blower motor operate in each speed position?

--

Go to Step 5

Go to Blower Motor 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, the 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 Bi-Level position.
  4. Place the A/C request switch in the ON position.
  5. Place both temperature switches 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 .

Did you find and correct the condition?

--

Go to Step 18

Go to Step 8

8
  1. Install a scan tool.
  2. Observe the Driver Temp Door Position and Passenger Temp Door Position in the HVAC scan tool data list.
  3. Adjust the air temperature switch.

Does the scan tool indicate the driver and passenger temp data values are within the specified parameter?

0-255 Counts

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 Temperature Valve Actuator Replacement .
    • Broken or binding linkages or air temperature door
    • An obstruction that prevents the air temperature door from operating within the 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 Testing for Intermittent Conditions and Poor Connections

10

Test the door control circuit of the air temperature actuator for the following conditions:

    • An open
    • High resistance
    • A short to ground
    • A short to voltage

Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

--

Go to Step 18

Go to Step 11

11

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

Did you find and correct the condition?

--

Go to Step 18

Go to Step 12

12

Important: Ensure that the HVAC control module 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 door control circuit of the air temperature actuator to a good ground.
  3. Place the air temperature switch from the coldest position to the warmest position.

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

0 V at cold

12 V at hot

Go to Step 13

Go to Step 15

13

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 .

Did you find and correct the condition?

--

Go to Step 18

Go to Step 14

14

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

    • A misaligned air temperature actuator--Refer to Temperature Valve Actuator Replacement .
    • Broken or binding linkages or air temperature door
    • An obstruction that prevents the air temperature door from operating within the 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 16

15

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 18

Go to Step 17

16

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

Did you complete the replacement?

--

Go to Step 18

--

17

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

Did you complete the replacement?

--

Go to Step 18

--

18

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2