2001 Nissan Altima temperature dial sticking; blows only cool air. Why?

Look under the steering wheel. There is a wire (the thickness of a coat hanger) that leads from the back of the temperature knob to a black piece of plastic with gear teeth in it. This piece is used to turn a white plastic knob with teeth to control the source of air entering the vents. In my situation, the knob became "stuck" at the central mix point, going no further into the cold side. I took the black plastic piece off (one screw) realigned the teeth, and screwed the piece back in. Works fine now. Use a groove in the edge of the black piece and a peg in the edge of the white piece to line the two up properly. I have to turn the dial slowly so it doesn't pop out of alignment again...but it does work.

Robert Scheid
March 2008