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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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2004 Impala: My heater..only blows..cold air

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My heater in my 2004 Impala only blows out cold air. What can I do to fix this?


First make sure the cooling system is full & with the engine at operating temperature check to make sure both heater hoses going into the firewall are hot with engine running,

If this is good you most likely have a bad temperature actuator.Before replacing the actuator,try this recalibration first.

Actuator Recalibration

Use the following steps to perform the calibration update:

  1. Turn OFF the ignition.
  2. Remove the battery positive voltage circuit fuse of the HVAC Control Module.Located in right side instrument panel junction block (end of dash) fuse # XXXXX FUSE 10 AMP

    Important: The module memory will not clear if the battery positive voltage circuit fuse is installed in less than 60 seconds.

  3. Wait 60 seconds.
  4. Install the fuse.
  5. Wait 60 seconds before moving the HVAC controls.
John and 2 other Chevy Specialists are ready to help you
Customer: replied 7 years ago.

Hey John: Cliff here. I tried what you suggested but it did not seem to work. Is replacing the temperature actuator something I can do or do I need to take it to the dealer?

Once again thank you for your help.



Cliff Barnhart

Here is info to help you replace the temperature actuator.I suggest looking at the actuator while moving the temperature control & see if the shaft moves.There is one on each side of the vehicle.Also have the system (body control module) scanned for failure codes to make sure it is not a open circuit causing this problem.



Temperature Valve Actuator Replacement - Left Side

  1. Remove the left instrument panel (I/P) insulator. Remove the knee bolster bracket bracket. Disconnect the electrical connector from the left air temperature actuator.
  2. Remove the mounting screws from the left air temperature actuator.
    Object Number: 833461  Size: SH

  3. Remove the left air temperature actuator.

    Object Number: 833461  Size: SH

  1. Position the left air temperature actuator. Align the slots in the electric actuator driver to the flats on the shaft.
  2. Align the locating hole to the alignment pin on the HVAC module case.
  3. Slide the actuator on the shaft. The actuator driver should seat completely onto the shaft and the mounting holes should be flush with the mounting screws on the HVAC module case.

    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.

  4. Install the mounting screws to the left air temperature actuator.

    Tighten the screws to 1.5 N·m (13 lb in).

  5. Connect the electrical connector to the left air temperature actuator.
  6. Install the knee bolster bracket bracket. Install the left I/P insulator. .
  7. Calibrate the actuator.