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Home >> Buick >> 2007 >> Lucerne CX >> Repair and Diagnosis >> External Pages >> Different car >> Section 222 (Heating, Ventilation And Air Conditioning) >> Diagnostic Information and Procedures >> Heating Performance Diagnostic (Auxiliary System)

Heating Performance Diagnostic (Auxiliary System)

WARNING: This page is about a different car, the 2006 Pontiac Montana SV6, 2006 Chevrolet Uplander, and 2006 Buick Terraza. However, it is still accessible from the selected car via links, so may be relevant.
Heating Performance Diagnostic (Auxiliary System)

Step Action Yes No
DEFINITION: Heating system performance of the auxiliary heater.
1 Were you sent here from Symptoms or another diagnostic table? Go to Step 2  Go to Too Cold in Vehicle
2
  1. Start the engine.
  2. Allow the engine to idle.
Does the engine reach a normal operating temperature?		 Go to Step 3  Go to Step 9 
3
    CAUTION: Refer to Moving Parts and Hot Surfaces Caution in Cautions and Notices.
  1. Allow the engine to idle.
  2. Select the warmest auxiliary temperature setting.
  3. Select the minimum auxiliary blower speed.
  4. Feel the temperature of the inlet and outlet auxiliary heater hoses.
Does the inlet heater hose feel warmer than the outlet heater hose?		 Go to Step 7  Go to Step 4 
4
  1. Install a thermometer into an auxiliary air outlet.
  2. Secure a thermometer on the outlet heater hose of the auxiliary heater core.
  3. Select the maximum auxiliary blower speed.
  4. Select the warmest auxiliary temperature setting.
  5. Record the temperature at the following locations:
    • The auxiliary air outlet
    • The auxiliary heater core outlet hose
  6. Compare the recorded temperatures.
Are the two temperature readings about equal?		 Go to Step 5  Go to Step 6 
5
  1. Inspect the following areas of the vehicle for cold air leaks:
    • The auxiliary HVAC module case
    • The auxiliary air ducts
  2. Perform any necessary repairs.
Is the repair complete?		 Go to Step 11  -
6 Inspect the auxiliary HVAC module for correct temperature door operation.
Does the temperature door operate correctly?		 Go to Step 11  Go to Step 10 
7
  1. Turn OFF the engine.
  2. Backflush the auxiliary heater core.
  3. Start the engine and allow the engine to idle.
  4. Select the minimum auxiliary blower speed.
  5. Select the warmest auxiliary temperature setting.
  6. Feel the temperature of the inlet and outlet heater hoses at the auxiliary heater core.
Does the inlet heater hose feel warmer than the outlet heater hose?		 Go to Step 8  Go to Step 11 
8 Replace the auxiliary heater core. Refer to Heater Core Replacement - Auxiliary .
Is the repair complete?		 Go to Step 11  -
9 Repair the low engine temperature concern. Refer to Engine Fails To Reach Normal Operating Temperature in Engine Cooling.
Is the repair complete?		 Go to Step 11  -
10 Repair the temperature door operation.
Is the repair complete?		 Go to Step 11  -
11 Operate the system in order to verify the repair.
Did you find and correct the condition?		 System OK Go to Step 2 
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