defroster not working on 1999 Jeep Wrangler

My son has a 1999 jeep wrangler that for some reason when the defroster is turned on everything comes out the floor tubes, and no matter which way you turn the flow knob everything still comes out the floor tubes....any help would be appreiciated

Asked by for the 1999 Jeep Wrangler
It sounds like your blend door has malfunctioned. This is the door that directs where the flow goes.

You may have to remove your dash and drain your A/C. it is usually a really big. Sorry for the bad news. You can try and buy a 1 yr subscription for all your vehicle repair information.
thanks for the info, now for the big do you fix this ??