I have a 2000 civic and the air is not working correctly. It either blows cold air when it's turned all the way to cold, or hot air when it's turned all the way to hot. If you put it in the middle then it just blows hot air. Even if you put it one click away from the cold air it still blows hot. The only way to make it blow cold air is to put it all the way to the left on cold air. Thanks in advance!

 

Check the heater cable and the air mix control system: