coming from under dash on the pass side sear the center of the dash. I have the AUTO climate control. The AC/Heat, the whole system is working fine, hot or cold. Today I noticed a clicking noise from a small black box for the lack of a better word, appeared to be the size of a small old flip phone, it has a power source plugged into. I noticed the noise today when I turned the temp control to hot. The clicking was there where ever I set the temp but the temp of the system still worked based on where I set the setting dial. It would go away if I turned to full hot or full cold. If I turned it real fast to and stopped at any place in the cool to hot range it may stop but if I just moved it slow it clicked, it went away after a good 4 or so minutes. When I pushed on the plug of the small unit the noise did change.
What is this unit?

 

On mine it was the blower motor. I replaced it with a blower motor that I got at a junkyard. The blower motor is under the glove box. There are some YouTube videos on how to replace it but it is just some screws and unplug it and remove it. It is pretty awkward to get under there and see the screws but otherwise it is very do-able yourself.

 

This is not the blower motor. I suspect it is the unit that controls opening and closing the blend door or what ever this car has to change the air from cold to hot or where ever in the middle you set it.

 

Yes, it is the air mix motor