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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 1418 (HVAC Systems - Automatic) >> Diagnostic Information and Procedures >> Too Cold in Vehicle - Auxiliary (VIN 3 including Envoy XUV) >> Test Description

Test Description

WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 2004 Oldsmobile Bravada, 2004 GMC Envoy XUV, 2004 GMC Envoy XL, 2004 GMC Envoy, and 2004 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.

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

  1. 2:  This test resets HVAC control module and checks for current air temperature actuator DTC.
  2. 4:  This checks for proper airflow for each auxiliary blower motor speed position.
Too Cold in Vehicle - Auxiliary (VIN 3 including Envoy XUV)

Step Action Yes No
Schematic Reference: HVAC Schematics 
Connector End View Reference: HVAC Connector End Views 
DEFINITION: The auxiliary heating is insufficient.
1 Did you perform the HVAC Diagnostic System Check? Go to Step 2  Go to Diagnostic System Check - HVAC Systems - Automatic 
  1. Recalibrate actuators. Refer to Re-Calibrating Actuators (Primary) Re-Calibrating Actuators (Auxiliary HVAC) .
  2. With a scan tool, observe the Heating and Air Conditioning DTC List.
Does DTC B0229, B0414, B0424, B3761 or B3770 set?
Go to Diagnostic Trouble Code (DTC) List  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 auxiliary blower motor operate in any of the speed positions?
Go to Step 4  Go to Blower Motor Inoperative - Auxiliary (VIN 6 excluding Envoy XUV)  or Blower Motor Inoperative - Auxiliary (VIN 3 including Envoy XUV) 
Does the auxiliary blower motor operate at the desired speed? Go to Too Cold in Vehicle  Go to Blower Motor Malfunction - Auxiliary (VIN 6 excluding Envoy XUV)  or Blower Motor Malfunction - Auxiliary (VIN 3 including Envoy XUV)