GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2003 🢒 Park Avenue 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 Too Cold in Vehicle

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

DEFINITION: The temperature cannot be adjusted, or the heating is insufficient.

1

Did you perform the HVAC Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic

2

Important:: In order to execute the HVAC Recalibration command, the scan tool disrupts keep alive memory (KAM) causing DTC B1652 (Loss of KAM) to be set as history.

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, perform the HVAC Recalibration command in Heating and Air Conditioning Special Functions.
  4. With a scan tool, observe the current DTC list in Heating and Air Conditioning.

Does the scan tool display DTC B1340, B1341, B1343, or B1344?

--

Go to Diagnostic Trouble Code (DTC) List

Go to Step 3

3

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 operate in each speed position?

--

Go to Step 5

Go to Blower Motor Malfunction

5

When the heater or the defroster is ON, does the customer concern occur?

--

Go to Step 6

Go to Step 16

6
  1. Start the engine.
  2. Turn OFF the HVAC controls.

Does the A/C compressor operate?

--

Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 7

7

Inspect the cooling system for the following conditions:

    • A low coolant level
    • A loose or worn accessory drive belt
    • A leaking radiator hose or heater hose
    • A kinked radiator hose or heater hose
    • A missing radiator cap pressure seal
    • A leaking radiator cap

Did you find and correct the condition?

--

Go to Step 36

Go to Step 8

8
  1. Turn ON the ignition, with the engine OFF.
  2. With scan tool observe the Left Temp Dr. Commanded parameter in Heating and Air Conditioning data list.
  3. Place the air temperature switch from the coldest position to the warmest position.

Does the scan tool indicate that the Left Temp Dr. Commanded parameter change?

--

Go to Step 9

Go to Step 32

9
  1. Turn ON the ignition, with engine OFF.
  2. Observe the drive shaft of the left air temperature actuator.
  3. With a scan tool, command the left air temperature actuator ON and OFF.

Does left air temperature actuator drive shaft rotate?

--

Go to Step 11

Go to Step 10

10
  1. Turn OFF the ignition.
  2. Disconnect the left air temperature actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a 3-amp fused jumper wire between the left air temperature door position signal circuit and the low reference circuit of the left air temperature actuator.
  5. With the scan tool, observe the Left Temp. Dr. Actual parameter.

Does the scan tool indicate that the Left Temp Dr. Actual parameter is equal to the specified value?

10 Counts

Go to Step 11

Go to Step 25

11
  1. Turn ON the ignition, with the engine OFF.
  2. With scan tool observe the Right Temp Dr. Commanded parameter in Heating and Air Conditioning data list.
  3. Place the right air temperature switch from the coldest position to the warmest position.

Does the scan tool indicate that the Right Temp Dr. Commanded parameter change?

--

Go to Step 12

Go to Step 32

12
  1. Turn ON the ignition, with engine OFF.
  2. Observe the drive shaft of the right air temperature actuator.
  3. With a scan tool, command the right air temperature actuator ON and OFF.

Does the right air temperature actuator drive shaft rotate?

--

Go to Step 15

Go to Step 13

13
  1. Turn OFF the ignition.
  2. Disconnect the right air temperature actuator.
  3. Turn ON the ignition, with the engine OFF.
  4. Connect a 3-amp fused jumper wire between the right air temperature door position signal circuit and the low reference circuit of the right air temperature actuator.
  5. With the scan tool, observe the Right Temp. Dr. Actual parameter.

Does the scan tool indicate that the Right Temp Dr. Actual parameter is less than the specified value?

10 Counts

Go to Step 14

Go to Step 27

14

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

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

Did you find and correct the condition?

--

Go to Step 36

Go to Step 29

15

Perform the Heating Performance Diagnostic. Refer to Heating Performance Diagnostic in Heating, Ventilation and Air Conditioning.

Did you find and correct the condition?

--

Go to Step 36

Go to Step 16

16

Verify the air temperature sensors for proper installation. Refer to the following procedures:

  1. Air Temperature Sensor Replacement - Upper Right Side
  2. Air Temperature Sensor Replacement - Upper Left Side
  3. Air Temperature Sensor Replacement - Lower Left Side
  4. Air Temperature Sensor Replacement - Lower Right Side

Did you find and correct the condition?

--

Go to Step 36

Go to Step 17

17
  1. Start the engine.
  2. Fully open all panel outlets.
  3. Place the temperature switch in the 24°C (75°F) position.
  4. Place the mode switch in the vent position.
  5. Set blower speed to illuminate 2 bars on the fan speed indicator.
  6. Place the right air temperature switch in the neutral position.
  7. 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 18

Go to Step 22

18
  1. Turn the engine OFF.
  2. Install a scan tool.
  3. Cover the right and left sunload sensors.
  4. Start the engine.
  5. Place the temperature switch in the 22°C (74°F) position.
  6. Place the right air temperature switch in the neutral position.
  7. With a scan tool, observe the Right and Left Solar Sensor data parameters in the Heating and Air Conditioning Open/Short data list.

Does the scan tool indicate that the Right and Left Solar Sensor data parameters are more than the specified value?

230  Counts

Go to Step 19

Go to Step 31

19
  1. Uncover the right and left sunload sensors.
  2. Direct the J 42220 Leak Detection Lamp at the right and then the left sunload sensors.

Do the counts change similarly and correspond to the proper sunload sensor?

--

Go to Step 20

Go to Step 31

20
  1. Install a thermometer near the upper right, upper left, lower right, lower left and inside air temperature sensors.
  2. With a scan tool, observe the Driver AC Duct Temp, Driver Htr. Duct Temp, Passenger AC Duct Temp, Passenger Htr. Duct Temp and Inside Air Temp data parameters in the Heating and Air Conditioning HVAC Sensor data list.

Do the scan tool temperatures differ from the thermometer temperatures by less than the specified value?

3°C (5°F)

Go to Step 21

Go to Step 23

21

Does the customer need to change the set temperature frequently in order to maintain comfort?

--

Go to Air Conditioning (A/C) System Does Not Maintain Set Temperature

System OK

22

Inspect for a blocked or disconnected aspiration hose.

Did you find and correct the condition?

--

Go to Step 36

--

23

Inspect for poor connections at the harness connector of the suspect 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 36

Go to Step 24

24

Test the suspect temperature sensor resistance. Refer to Sensor Resistance Table .

Is the resistance measurement close to the value of the Sensor Resistance Table?

--

Go to Step 32

Go to Step 33

25

Test the left air temperature door position signal circuit of the left air temperature actuator for an open, a high resistance, 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 36

Go to Step 26

26

Test the low reference circuit of the left air temperature actuator for an open or high resistance. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 36

Go to Step 32

27

Test the right air temperature door position signal circuit of the right air temperature actuator for an open, a high resistance, 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 36

Go to Step 28

28

Test the low reference circuit of the right 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 36

Go to Step 32

29

Inspect for poor connections at the harness connector of the suspect air temperature actuator. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 36

Go to Step 30

30

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

Did you complete the replacement?

--

Go to Step 36

--

31

Inspect for poor connections at the harness connector of the suspect sunload 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 36

Go to Step 34

32

Inspect for poor connections at the harness connector of the instrument panel integration module (IPM). 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 36

Go to Step 35

33

Replace the suspect temperature sensor. Refer to the following procedures:

Did you complete the replacement?

--

Go to Step 36

--

34

Replace the suspect sunload sensor. Refer to Sun Load Sensor Replacement - Left Side or Sun Load Sensor Replacement - Right Side .

Did you complete the replacement?

--

Go to Step 36

--

35

Important:: Perform the recalibration procedure for the IPM.

Replace the IPM. Refer to Instrument Panel Module Replacement in Body Control System.

Did you complete the replacement?

--

Go to Step 36

--

36

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2