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Test Description

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

  1. 2:  This step ensures that the primary HVAC system is functioning properly.
  2. 3:  The DTC's listed could set if a calibration of the actuators is performed.
  3. 6:  If the condition does not occur when an A/C request has been made then you must bypass the A/C performance test procedures.
  4. 7:  Performing the Air Conditioning System Performance Test ensures that the A/C system is operating properly for further testing.
  5. 8:  This step ensures that the rear auxiliary HVAC control module is able to move the auxiliary air temperature actuator.
  6. 9:  This step ensures that the front auxiliary HVAC control assembly is able to move the auxiliary air temperature actuator.
  7. 11:  The infrared sensor is located between the auxiliary blower motor switch and the auxiliary temperature switch on rear auxiliary HVAC control module. It has a glass cover protecting the sensor which is integral to the rear auxiliary HVAC control module.
Too Hot in Vehicle - Auxiliary (w/o Sunroof)

Step Action Values Yes No
Schematic Reference:  HVAC Schematics  
DEFINITION: Auxiliary air temperature can not be adjusted from one or both auxiliary controls or auxiliary cooling is insufficient.
1 Did you perform the HVAC Diagnostic System Check? - Go to Step 2  Go to Diagnostic System Check - HVAC Systems - Automatic 
2  The auxiliary HVAC control assembly cannot request A/C compressor operation. An A/C request must be generated by the HVAC control module to provide cooled airflow through the auxiliary system.
Does the HVAC control module operate and provide sufficient cooling?		 - Go to Step 3  Go to Too Hot in Vehicle 
3 
IMPORTANT: If during this diagnostic procedure the HVAC control module is disconnected a recalibration of actuators must be performed to avoid misdiagnosis.
  1. Recalibrate actuators. Refer to Re-Calibrating Actuators .
  2. Install a scan tool.
  3. Turn ON the ignition, with the engine OFF.
  4. Observe the current DTC list in Heating and Air Conditioning using the scan tool.
Does the scan tool display DTC B0229, B0414, B0434, B3761 or B3764?		 - Go to Diagnostic Trouble Code (DTC) List  Go to Step 4 
4
  1. Turn ON the ignition, with the engine OFF.
  2. Select REAR CNTL on the front auxiliary HVAC control assembly.
  3. Place the A/C auxiliary blower motor switch in each speed position.
Does the auxiliary blower motor operate at all?		 - Go to Step 5  Go to Blower Motor Inoperative - Auxiliary (W/O Sunroof) Blower Motor Inoperative - Auxiliary (W/Sunroof or Heat Only) 
5 Does the auxiliary blower motor operate at the desired speed in each speed position? - Go to Step 6  Go to Blower Motor Malfunction - Auxiliary (W/O Sunroof) Blower Motor Malfunction - Auxiliary (W/Sunroof or Heat Only) 
6  Does the Auxiliary Too Hot In Vehicle concern occur when A/C cooling is desired? - Go to Step 7  Go to Step 8 
7  Perform the refrigerant system performance test. Refer to A/C SYSTEM PERFORMANCE TEST .
Did you find and correct the condition?		 - Go to Step 22  Go to Step 8 
8 
  1. With a scan tool, observe the Aux. Mix Door Actual data parameter in the Auxiliary ECC Data list.
  2. Select REAR CNTL on the front auxiliary HVAC control assembly.
  3. Place the auxiliary air temperature switch on the rear auxiliary HVAC control module from the coldest to warmest position.
Do the counts change?		 - Go to Step 9  Go to Step 13 
9 
  1. Select OFF on the front auxiliary HVAC control assembly.
  2. Place the front auxiliary air temperature switch from the coldest to hottest position.
Do the counts change?		 - Go to Step 10  Go to Step 14 
10 Check the auxiliary upper outlet and auxiliary lower outlet temperature sensors for proper installation. Refer to Air Temperature Sensor Replacement - Upper Auxiliary  and Air Temperature Sensor Replacement - Lower Auxiliary .
Did you find and correct the condition?		 - Go to Step 22  Go to Step 11 
11  Place your hand directly over the infrared sensor on the rear auxiliary HVAC control module.
Do the counts change?		 - Go to Step 12  Go to Step 18 
12
  1. Turn ON the ignition, with the engine OFF.
  2. Observe the Aux. Upper Outlet Temp. and the Aux. Lower Outlet Temp. parameter in the Auxiliary ECC Data list.
  3. Turn OFF the ignition.
  4. Measure the resistance of the upper auxiliary and the lower auxiliary air temperature sensors. Refer to Sensor Resistance Table (Ambient and Inside Air Temp - ohms)  or Sensor Resistance Table (Upper, Lower and Aux Air Temp - ohms) .
  5. Compare the resistance of the sensor to the count value of the scantool.
Does the resistance measure near the sensor resistance table value?		 - System OK Go to Step 16 
13 Test the low reference circuit of the front auxiliary HVAC control assembly for an open or high resistance. Refer to CIRCUIT TESTING and WIRING REPAIRS .
Did you find and correct the condition?		 - Go to Step 22  Go to Step 15 
14 Test the front auxiliary temperature door control circuit of the front auxiliary HVAC control assembly for an open or high resistance. Refer to CIRCUIT TESTING and WIRING REPAIRS .
Did you find and correct the condition?		 - Go to Step 22  Go to Step 15 
15
  1. Measure the resistance from the front auxiliary temperature door control terminal to the low reference terminal on the front auxiliary HVAC control assembly.
  2. Place the auxiliary air temperature switch from the coldest to hottest position.
Does the resistance change?		 - Go to Step 18  Go to Step 17 
16 Inspect for poor connections at the harness connector of the suspect air temperature sensor. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS .
Did you find and correct the condition?		 - Go to Step 22  Go to Step 19 
17 Inspect for poor connections at the harness connector of the front auxiliary HVAC control assembly. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS .
Did you find and correct the condition?		 - Go to Step 22  Go to Step 20 
18 Inspect for poor connections at the harness connector of the auxiliary HVAC control module. Refer to TESTING FOR INTERMITTENT AND POOR CONNECTIONS and CONNECTOR REPAIRS .
Did you find and correct the condition?		 - Go to Step 22  Go to Step 21 
19 Replace the suspect air temperature sensor. Refer to Air Temperature Sensor Replacement - Upper Auxiliary  or Air Temperature Sensor Replacement - Lower Auxiliary .
Did you complete the replacement?		 - Go to Step 22  -
20 Replace the front auxiliary HVAC control assembly. Refer to HVAC Control Assembly Replacement - Front Auxiliary .
Did you complete the replacement?		 - Go to Step 22  -
21 Replace the auxiliary HVAC control module. Refer to HVAC Control Module Replacement - Auxiliary .
Did you complete the replacement?		 - Go to Step 22  -
22 Operate the system in order to verify the repair.
Did you correct the condition?		 - System OK Go to Step 2 
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