Sierra Classic 2500 4WD V8-6.0L (2007)
Control Module HVAC: All Technical Service Bulletins
A/C - HVAC Control Module Lockup During Reprogramming
Bulletin No.: 06-01-39-014
Date: December 06, 2006
INFORMATION
Subject:
Information On HVAC Control Module Lockup During Reprogramming
Models:
2007 Cadillac Escalade Models
2007 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2007 GMC Sierra, Yukon Models
with Automatic Temperature Control HVAC System (RPO CJ2)
The purpose of this bulletin is to alert technicians to a condition they may encounter while trying to reprogram a Heating, Ventilation and Air
Conditioning (HVAC) control module. If the HVAC control module reprogramming event is interrupted, the control module may go into a "lock up"
mode. This will cause the HVAC control module to disable communications and a second try at reprogramming will fail. The interruption may be caused
by a software anomaly inside the HVAC control module.
If the HVAC reprogramming event was interrupted and a subsequent reprogramming attempt fails, perform a battery reset. This can be accomplished by
either removing and reinstalling the HVAC BATT fuse, located in the underhood fuse block, or by disconnecting and reconnecting the HVAC control
module connector C2. Connector C2 is grey in color with 16 cavities. Once the battery reset has been performed, the HVAC control module will resume
communications and will then be able to be reprogrammed.
The Warranty Parts Center (WPC) has received HVAC control modules that have been returned and described as non-functional but were tested with no
problems found. If the module has been replaced due to a failed second attempt at reprogramming caused by the lock up, the module will be returned and
charged back to the dealer. Technicians must also remember that after a new HVAC control module has been installed into a vehicle, it must be
programmed, otherwise it will not be functional.
Disclaimer
