Because there are variations depending on the specific HVAC configuration (different options were available), you might need to consult a repair manual specific to your vehicle's year, make, model, and options to pinpoint its exact location with respect to other components within the dash. A diagram would be very helpful.
Caution: Removing the glove box and accessing the actuator requires some disassembly. If you're not comfortable with this, it's best to take it to a qualified mechanic.