I have a 05' Durango, and just over the last days or so I noticed when I initially turned on the vehicle I would hear a clicking sound coming from the heater. The sound goes away after a few seconds, I am wondering if this could be the actuator or something else?

 

Don't know anything about the 2nd gen Durano's hvac system, but if it depends on the fan speed setting it could be the blower. If not it might be an actuator, but I don't know how that all works.