Clicking noise in radio area.wont go away on 2005 Ford Expedition

Husband started up our Expedition this morning and he got to listen to what sounded like the tape deck clicking all the way to work. What could it be? He put tape in and took out (didn't work), tried turning vehicle off and on (didn't work) help please.

Asked by for the 2005 Ford Expedition
sounds like temperature door actuator on a/c. try changing temp on a/c to see if it changes or stops. if it does, will need an actuator for temp door.