Air Door Actuators

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4S Facebook Air Door Actuators


Four Seasons®, your complete source for HVAC products, now includes a full line of all new Air Door Actuators, a key component for driving comfort and air ventilation.  Made from premium materials, precision gears and quality soldered connections, Four Seasons® air door actuators undergo rigorous testing to ensure O.E. fit, form and function. 


Four Seasons® performs thorough testing to ensure every air door actuator we offer matches O.E. fit and performance.

Testing Includes: 

  • Function
    • Voltage Signal Input/Output: Directional or Operational
    • Operational Range
  • Critical Dimensions 
    • Mounting Configuration
    • Drive Mating/Orientation
  • Connector Fitment with O.E. Harness
  • Endurance Testing
    • 5,000 Full-Range Cycles

Did You Know?

Typically, vehicles have 3 or 4 actuators. Vehicles with rear controlled HVAC will often have additional actuators to control the auxiliary unit, bringing the total per vehicle to as many as 6!

Functions of Air Door Actuators

Temperature Blend Door Actuators: The temperature blend door actuators control the temperature of the air flowing from the vents by mixing hot and cold air from the heater core and the evaporator core.

Mode Door Actuators: The mode door actuator controls what vents have air flow, i.e. floor, panel or front, defrost, or any combination of those.

Recirculation Door Actuators: The recirculation door actuator controls the intake of air into the system, either bringing outside air in or using inside air in recirculation.

Common Failures

Failures of the air door actuators often lead to the air door becoming stuck in one position, leading to improper ventillation.

Electrical Failures:

  • Motor Failure
  • Poor Electrical Connections
  • Internal Electrical Components on the PCB fail

Mechanical Failures:

  • Broken Gears
    • Split in the main drive gear
    • Broken teeth on small gears

Functional Failures:

  • Internal feedback for the actuator's position no longer functions properly, often resulting in an intermittent failure


The complexity of replacing air door actuators varies greatly between applications. While some actuators are located just under the dash and can be replaced in an hour or less, others require a complete removal of the dash or HVAC case. These replacements can take up to 8 hours of labor to complete in a confined space.