Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET2004TAHOE 4WD V8-5.3L VIN TREPAIR AND DIAGNOSISTECHNICAL SERVICE BULLETINSCUSTOMER INTERESTA/C - DEFAULTS TO DEFROST MODE/POOR CONTROL
2004 Chevrolet Tahoe 4WD V8-5.3L VIN T
A/C - Defaults To Defrost Mode/Poor Control
2004 Chevrolet Tahoe 4WD V8-5.3L VIN TSECTION A/C - Defaults To Defrost Mode/Poor Control
Bulletin No.: 04-01-38-008
Date: June 17, 2004
TECHNICAL
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
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 the table.
Disclaimer
Date: June 17, 2004
TECHNICAL
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
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 the table.
Disclaimer
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.