HVAC actuators

[jwalker]

Is there a specific actuator / blend door that controls recirculating as well as defrosting? I'm aware that theres 4 actuators on a 2004 Silverado, dual climate control.

[Doug_Scott]

There pretty much has to be since recirculation (or MAX air on older vehicles)can be used on defrost and panel modes, but not on floor or any of the combination modes (defrost and floor for example)

[jwalker]

What im looking for is which one it is, where its at in the dash, and any applicable part numbers for the actuator.