Defroster,heater,vents,airconditionig not working when turned on

Question. Is the flapping at a very fast pace that would indicate the speed of a fan blade hitting something? If so, you may be on to something there such as a misplaced gasket or something has dropped/fallen into the blower box via a vent.

If it is not that speed then see the following..

Hope I can give you some direction. Speaking from a generic sense all ac/heaters these days have a door or doors in the blower box that control air flow from the main part of the box to different positions when you ask for vent, heater, mix, defrost etc..

Most these days are operated with a small electric servo/motor and unfortunately the mostly have plastic gears that wear and can "thump-thump" as the motor cycles trying to open or close the flapper door.

Try to change the air direction from Max AC to regular ac to heater, defroster, bi-level etc all with the AC switch in the on position if you have a separate on/off switch.

Listen to the sound and see if it comes and goes with a different location of the selector switch.

One last question. Does it happen at idle or driving down the road at any particular speed?

Lets start with that and see what happens. This is interesting.

Good luck!

the dampers are failing.
first check fuses.... as always.....
ok some cars have cable dampers others use elect. motor dampers
the FSM covers the tests, on this. electric is hardest.
if cable drive, just look are they working>? simple it is.
the cable most move on both ends, is it? and still connected>?

Could be the main control panel. The ac clutch will engage if it gets power and the system is full of freon. The air should switch to the other vents even if the ac clutch does not engage.
You may need a shop manual to get the wiring diagrams to troubleshoot the system.

make him do it again... ?

Yes, except for the vent setting. AC or defrost will engage the compressor, but vent should be just outside air.
Does the blower work ?

Sounds like the flap valve in your vent system that allows air to go to the defrosters is either jammed or broken. Unfortunately you will have to take the vent system apart to look.

replace the the heater control panel..real common on gm trucks

probably blew a fuse ,also sounds like the switch may have broken inside the dash

This is the KIA tech site. Free to register and use. It lists the repair tech manuals, Sevice Bulletins, How-to's, and troubleshooting guides the factory trained repair guys use:
http://www.kiatechinfo.com/index.asp

sounds like the vent flap is stuck