GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 Envoy - 2WD 🢒 HVAC 🢒 HVAC - Automatic 🢒 Too Cold in Vehicle - Auxiliary

Too Cold in Vehicle - Auxiliary VIN 3

Diagnostic Aids

The air temperature for the flow through console is regulated by the air temperature actuator for the primary HVAC system. Ensure the primary HVAC system is functioning properly.

Test Description

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

  1. This test resets HVAC control module and checks for current air temperature actuator DTC.

    2.

  2. This checks for proper airflow for each auxiliary blower motor speed position.

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 Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Recalibrate actuators. Refer to Actuator Recalibration .
  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 - Vehicle

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 Auxiliary Blower Motor Inoperative

4

Does the auxiliary blower motor operate at the desired speed?

Go to Too Cold in Vehicle

Go to Auxiliary Blower Motor Malfunction