Hyundai Repair: 2007 Hyundai Accent temperature knob will not turn. How do I unstick it?, hyundai accent, interior temperature

Question
The temperature knob that controls the interior temperature in my Hyundai seems to be very stuck. There is a crack in it, and it will not move at all from the very cold position. The small light on the knob is not working either. I can't seem to pull it out, and I don't want to risk affecting the AC (which does work). What should I do?

Answer
If you have a crack in the knob, you'll need to replace the knob as it will do a poor job of turning the shaft in the heater control.  The knob should pull off.  Note that the crack shouldn't prevent the knob from turning-- in most cases, the knob will turn but the control behind it won't.

If the control behind the knob is in fact stuck, you'll investigate whether the cable is appropriately attached to the heater box and back of the heater control.  Check the heater box first, as this will typically not require disassembly.  Simply stick you head under the dash and look up at the heater box (behind the center of the dash).  Watch the movement as you turn (or attempt to turn) the knobs on the heater control.  As each cable moves, it should in turn move the lever on the side of the box fully one direction and the other.  If it doesn't, the lever may have come loose, the cable may not be attached to the clip on the heater box, or the cable may be damaged.  Very rarely is the heater control assembly itself damaged, and most times, the problem occurs after removal of the heater control assembly for one reason or another.  If the heater control assembly is pulled out without disconnecting the cables from the heater box, you'll typically get one of the problems I've mentioned above due to pulling too hard on the cables.

According to the parts catalog, the bulbs in the heater control assembly are not serviceable, but I tend to view this with some suspicion.  To find out for certain, you'll need to remove the heater control assembly and see if you can take the bulbs out of it.  As alluded to above, first disconnect the cables from the heater box.  Then, the facia to which the heater control is attached should snap out of the dash.