Information on Vehicles with HVAC Control Module A/C and Recirculation Indicators Flashing (09-01-38-004)

Publication date: 2009-07-31
Reference number: 09-01-38-004

Information on Vehicles with HVAC Control Module A/C and Recirculation Indicators Flashing

TECHNICAL SERVICE BULLETIN

Reference Number(s): 09-01-38-004, Date of Issue: July 31, 2009

Affected Model(s):

2008-2010 Buick Enclave; 2007-2010 Cadillac Escalade Models; 2007-2010 Chevrolet Avalanche, Silverado, Suburban, Tahoe; 2009-2010 Chevrolet Traverse; 2007-2010 GMC Acadia, Sierra, Yukon, Yukon XL; 2007-2010 Saturn OUTLOOK

Condition/Concern

IMPORTANT: DO NOT replace the HVAC Control Module for a flashing A/C Indicator or flashing Recirculation Indicator, as this is normal operation.

Some customers may comment on any of the following conditions:

The Air Conditioning (A/C) indicator on the heating ventilation and air conditioning (HVAC) control module flashes then turns OFF after they press the A/C button.
The Recirculation indicator on the HVAC control module flashes then turns OFF after they press the Recirculation button.
The passenger (PASS) temperature setting flashes then turns OFF after they press the PASS button.
The driver and passenger temperature settings revert to previous temperature settings when changing from defrost to bi-level, vent, floor or defog.

This is normal operation for the HVAC Control Module and indicates that the A/C, Recirculation and Passenger functions are not available at this time.

The following parameters are reasons that the A/C functions may not be available (calibrated values vary by program):

Ambient air temperature (AAT) is too cold (if equipped with Ambient Air Temperature Sensor)
Vehicle system voltage is less than 9.5 volts
Refrigerant pressure is too low
Refrigerant pressure is too high
Engine coolant temperature (ECT) is too high
Engine is not in RUN
HVAC Control Head is in the OFF position

The following mode settings are reasons Recirculation may not be available:

Mode switch set on Floor
Mode switch set on Defog
Mode switch set on Defrost

The following mode setting is the reason the passenger mode may not be available:

The mode switch is set on Defrost.

NOTE: The reason(s) A/C is currently disabled can be viewed with a Tech 2® by navigating to HVAC Data display and viewing the A/C Permission parameter.

Recommendation/Instructions

NOTE: To maintain the highest level of customer satisfaction, INFORM the customer of all of the following conditions:

The flashing A/C indicators on the HVAC control module represent normal operation and indicate that the A/C, Recirculation and/or Passenger functions are not available at this time.
Changing the passenger temperature setting while in the Defrost mode will change the Driver temperature setting.
Changes made to temperature settings while in Defrost mode will revert to the previous settings upon returning to Bi-level, Vent, Floor or Defog.

Consult the appropriate vehicle Service Information (SI) for a detailed HVAC Description and Operation.