This guy wants me to buy this 05 Ford but I hear a clicking noise in dash

It needs to be checked by a shop. The clicking could be a bad actuator. But any used car purchase should have the car looked at by a tech before you buy it.

I agree with Gillespie's,have it checked! it could be a blend door actuator ( I could fill a 50 gallon barrel with all of the ones I replaced) or the door inside the plenum itself.

Most fords I have these problems, it's an easy fix. It's just a door motor for the air ducts. Replace it and the noise should go away.