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John, Master A.S.E Automotive technician
Category: Chevy
Satisfied Customers: 9176
Experience:  A.S.E MasterTechnician A1-A8 w/L1,38 years experience General Motors Master Technician
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2006 trailblazer ext. Clicking noise from right rear. heating/ac

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2006 trailblazer ext. Clicking noise from right rear. heating/ac actuator? Thats what some sites say. How can i fix it?

Hello & Welcome,


Your problem is most likely an auxiliary actuator .here is some info to help you replace it.

Rear Quarter Trim Panel Replacement - Right Side (TrailBlazer EXT, Envoy XL)

    Object Number: 799604  Size: SH

  1. Remove the cargo shelf.
  2. Tumble the third row seats to the cargo position.
  3. Remove the right body side window rear garnish molding.
  4. Remove the right body side window forward garnish molding.
  5. Remove the liftgate sill plate. Remove the right rear door sill panel. Remove the lower seat belt anchor bolt.
    Object Number: 799086  Size: SH

  6. Release the five screws that retain the rear quarter trim panel to the body.
  7. Remove the rear quarter trim panel from the vehicle.

Auxiliary Temperature Valve Actuator Replacement

  1. Remove the right rear quarter trim panel. Disconnect the electrical connector from the air temperature actuator.
  2. Remove the retaining screws from the air temperature actuator.
    Object Number: 814583  Size: SH

  3. Remove the air temperature actuator (1) from the rear HVAC module.

    Object Number: 814583  Size: SH

  1. Install the air temperature actuator (2) to the rear HVAC module.

    Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

  2. Install the screws to the actuator.

    Tighten the screws to 1.9 N·m (17 lb in).

  3. Connect the electrical connector to the air temperature actuator.
  4. Recalibrate the air temperature actuator. .
  5. Install the right rear quarter trim panel.
Customer: replied 6 years ago.
What is causing all the clicking noise? Why did it happen?
The actuator has an internal failure of a position switch.
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