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Test Description

WARNING: This page is about a different car, the 2004 Pontiac Aztek and 2004 Buick Rendezvous. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 3:  This checks for A/C compressor clutch always on.
  2. 7:  This test is to insure cooling system is operating normally.
  3. 10:  The aspirator tube connects to the rear of the HVAC control module. The aspirator tube is used to draw air past the inside air temperature sensor.
Too Cold in Vehicle

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 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
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. Observe the Diagnostic Trouble Code (DTC) List in Heating and Air Conditioning.
Does the scan tool display any DTC B0165, B0166, B0408, B0418 or B0233?		 - Go to Diagnostic Trouble Code (DTC) List  Go to Step 3 
3 
  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 4 
4 Place the blower motor switch in each speed position.
Does the blower motor operate in any of the speed positions?		 - Go to Step 5  Go to Blower Motor Inoperative 
5 Does the blower motor operate in the desired speed(s)? - Go to Step 6  Go to Blower Motor Malfunction 
6
  1. Place the blower motor switch in the maximum speed position.
  2. Place the mode switch in the vent position.
  3. Place the recirculation switch in the ON and OFF positions.
Does the recirculation door operate properly?		 - Go to Step 7  Go to Air Recirculation Malfunction 
7  Perform the heater performance diagnostic. Refer to Heating Performance Diagnostic in Heating, Ventilation and Air Conditioning.
Did you find and correct the condition?		 - Go to Step 21  Go to Step 8 
8
  1. Turn ON the ignition, with engine OFF.
  2. With a scan tool, command the right and left air temperature actuators Hot and Cold.
  3. Observe the Right Temp Door Position and the Left Temp Door Position parameters.
Do the counts change when actuators are commanded?		 - Go to Step 9  Go to Step 13 
9
  1. Install a thermometer near the inside air temperature sensor.
  2. With a scan tool, observe the Inside Air Temp data parameters in the Heating and Air Conditioning Data list.
Does the scan tool indicate the sensor temperature are within 3°C (5°F) of the thermometer temperatures?		 - Go to Step 11  Go to Step 10 
10  Inspect for a blocked aspirator tube of the HVAC control module.
Did you find and correct the condition?		 - Go to Step 21  Go to Step 17 
11
  1. Turn the engine OFF.
  2. Install a scan tool.
  3. Cover the sunload sensor.
  4. Start the engine.
  5. Adjust driver side temperature to 22°C (72°F).
  6. With a scan tool, observe the Sunload Sensor data parameter in the Heating and Air Condition data list.
Does the scan tool indicate that the Sunload Sensor parameter is greater than the specified value?		 230 Counts Go to Step 12  Go to Step 16 
12
  1. Uncover the sunload sensor.
  2. Direct a light source at the sunload sensor.
Does the voltage change?		 - System OK Go to Step 16 
13 Test the suspect actuator door control circuit for a short to voltage, short to ground, open or high resistance. Refer to Circuit Testing and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 21  Go to Step 14 
14 Test the suspect actuator ignition 3 voltage circuit for a short to ground, open or high resistance. Refer to Circuit Testing and Connector Repairs in Wiring Systems.
Did you find and correct the condition?		 - Go to Step 21  Go to Step 15 
15 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 21  Go to Step 19 
16 Inspect for poor connections at the harness connector of the 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 21  Go to Step 18 
17 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 21  Go to Step 20 
18 Replace the sunload sensor. Refer to Sun Load Sensor Replacement .
Did you complete the replacement?		 - Go to Step 21  -
19
IMPORTANT: Perform the recalibration procedure for the air temperature actuator
Replace the suspect air temperature actuator. Refer to Air Temperature Actuator Replacement - Right  or Air Temperature Actuator Replacement - Left .Did you complete the replacement?		 - Go to Step 21  -
20
IMPORTANT: Perform the recalibration procedure for the HVAC control module.
Replace the HVAC control module. Refer to HVAC Control Module 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 3 
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