I looked all around the forum and couldn't find anything about this, only found stuff about AC compressors and stuff like that, this problem I've got I think is pretty simple...My heater temp knob is really hard to turn sometimes in my 93 Accord. It got to the point where the heater knob broke so I ordered a new one. Haven't put it on yet because I want to fix this problem. Sometimes I'll turn it and it's kinda hard to get it from all the way cold to all the way hot or vice-versa and when I let go of the knob it'll go back to the position it was in a second earlier. I'm guessing I need a new heat control box maybe but maybe it's an easy fix if I open it up? I know everybody's had a broken heater control knob and hopefully somebody's had this problem and knows the fix. Thanks!

The heater control knob does two things when you turn the knob. It moves a flapper valve in the heater control box and also opens and closes the water inlet valve on the passenger side of the engine compartment. Try disconnecting the wire to the water inlet valve and if it now moves easily replace the valve. If not, check the heater control box. Sometimes something gets jammed on the flapper valve.