Document ID: 1528080
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2004 GMC Truck GMC K Sierra - 4WD | Sierra, Silverado (VIN C/K) Service Manual | HVAC | Bulletins By Category |
Technical | Document ID: 1528080
#04-01-38-008: HVAC System Cannot Be Controlled Or
Defaults To Defrost Mode (Repair HVAC Actuator
Harness) - (Jun 17, 2004)
Subject:
HVAC System Cannot be Controlled or Defaults to Defrost
Mode (Repair HVAC Actuator Harness)
Models:
2003-2005 Cadillac Escalade, Escalade ESV, Escalade EXT
2003-2005 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2003-2005 GMC Sierra, Yukon, Yukon XL
Condition
• Some customers may comment that they cannot control the HVAC (heating, ventilation and
air conditioning) system. Others may comment that the HVAC system defaults to the Defrost
mode.
• Technicians may find that the following diagnostic trouble codes have set:
• B0229 Recirculation Actuator
• B0414 Left Air Temperature Actuator
• B0424 Right Air Temperature Actuator
• B3770 Mode Actuator
Cause
The HVAC actuator harness may contact a sharp edge on the instrument panel support brace,
causing a rub through condition and a ground out of the actuator control and/or feedback circuits.
Correction
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Locate the HVAC actuator harness contact point shown by the arrow in the above illustration. The
illustration is of the instrument panel with the instrument panel compartment door opened and
folded downward. The actuator harness is located in the left side of the opening in the instrument
panel.
Technicians are to inspect the HVAC actuator harness for contact with the instrument panel support
brace. Repair any damage to the actuator harness wiring and install protective plastic conduit over
the harness. Install friction tape over the sharp edge of the instrument panel brace. Clear the
diagnostic trouble codes and verify proper HVAC system operation.
Warranty Information
For vehicles repaired under warranty, use:
Labor
Operation
N6642
Description
Labor Time
Wiring And/Or Connector - HVAC System Repair Or Replace
Use applicable labor
operation time.
GM bulletins are intended for use by professional technicians, NOT a
""do-it-yourselfer"". They are written to inform these technicians of
conditions that may occur on some vehicles, or to provide
information that could assist in the proper service of a vehicle.
Properly trained technicians have the equipment, tools, safety
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WE SUPPORT
VOLUNTARY
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Document ID: 1528080
instructions, and know-how to do a job properly and safely. If a
condition is described, DO NOT assume that the bulletin applies to
your vehicle, or that your vehicle will have that condition. See your
GM dealer for information on whether your vehicle may benefit from
the information.
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TECHNICIAN
CERTIFICATION
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