heater/air vent problems

the switch on my heater controls sems like it switches but no heat will come out of the vents; cool air blows out instead. when i bought the car the guy showed me teh heater worked, he moevd somethign under/behind the dashboard near the floorboard. im not exactly sure but i think he switched a vent on the bottom or somethign. but i need help trouble shooting to fix this.

hmmmmmmmmmmmmmmm try looking on drivers side or passenger sides for cables that clip onto a lil arm...
move the heater controlla rm your having problem with and see which cable moves.
if that no work do this way, move each cable up or down manually and see which one moves the affected adjust on the dash..

is it snapped into place? is the cable off?
try adjusting it:

Gently slide the cable outer housing back from the end enough to take up any slack in the cable, but not enough to make the control lever move. Then, snap the cable housing into the clamp.

also, what year is it?
our 99' and down use cables, not rotary dials

thanks for all your replies. i was able to fix my problem. it may not be permanantly fixed but i got it to where it will switch back and forth. i just have to be gental about it :) thanks all \nn/

Hyundai had to replace my heater. They said the heating core blew, which I don't think was true. It was going to be about 400 buck. Funny thing, the mechanic didn't know my car was under extended warranty. :evillol: Then that second heater also did what you described. This time, a different mechanic (warranty was over) did something where he left the switch permanently on a mixture of defrost for the windshield and a little for my toes. I've got it stuck that way and have had it like that for about 3 years.

if your core blew, youd know it right away and youd be loosing coolant