Document ID: 1528080 Page 1 of 3 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 © 2013 General Motors Corporation. All rights reserved. http://localhost:9001/si/showDoc.do?docSyskey=1528080&from=bcpi 4/3/2013 Document ID: 1528080 Page 2 of 3 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 http://localhost:9001/si/showDoc.do?docSyskey=1528080&from=bcpi WE SUPPORT VOLUNTARY 4/3/2013 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. http://localhost:9001/si/showDoc.do?docSyskey=1528080&from=bcpi Page 3 of 3 TECHNICIAN CERTIFICATION 4/3/2013