Certain HVAC Control Heads Not Reprogrammable (03-01-38-003)

Publication date: 2003-04-01
Reference number: 03-01-38-003

CERTAIN HVAC CONTROL HEADS NOT REPROGRAMMABLE

TECHNICAL SERVICE BULLETIN

Reference Number(s): 03-01-38-003, Date of Issue: April 2003

CHEVROLET:	2003 Chevrolet TrailBlazer, TrailBlazer EXT
GMC:	2003 GMC Envoy, Envoy XL
OLDSMOBILE:	2003 Oldsmobile Bravada
SECTION:	01 - HVAC

SERVICE INFORMATION

This bulletin is being issued to alert technicians that a heating, ventilation and air conditioning (HVAC) control head was used in production vehicles that can be programmed only one time. The control head was used in vehicles with both manual (CJ3) and automatic (CJ2) HVAC systems produced between mid October 2002 through early January 2003.

The HVAC control head used during this period cannot be reprogrammed using TIS 2000. The HVAC module part numbers as seen on the Tech2® are 15202099, 15202100, 15202101 and 15202102. A message will appear on the TIS 2000 screen with a warning not to reprogram these part number modules.

If a technician attempts to reprogram this module, the module will lock up and become totally non-functional. These modules already have an updated calibration to address the issues mentioned in Corporate Bulletin Number 02-01-39-005 HVAC SYSTEM INOPERATIVE FOR A DRIVE CYCLE, POOR HVAC SYSTEM PERFORMANCE IN HIGH AMBIENT TEMPERATURES (UPDATE HVAC CONTROL MODULE SOFTWARE). All HVAC control heads received from GMSPO for service replacement are a different part number and they are reprogrammable.