I have a 99 chevy silverado, something is wrong with my heater controls. the everything works ok except the middle knob that controls the temp, it appears to be stuck on hot. I thought it was the swich so I replaced that, but it is still stuck on hot, I cant get the temp to cool down at all.

any ideas as to what is wrong would be greatly appricated.:banghead:

Had the same thing happen on my 2001. There is a motor by the floor that controls the cold/hot mixture. This moter was worn and not powerful enough to switch it back to cold and it would stay on hot. Replacement of the moter (about $65) took care of the problem.

do you know were the motor is located?

On the passenger side, behind the center console, just above the carpet (i.e. on the bottom of the vent tubing. It is square with two bolts holding it in, about 3 1/2" X 3 1/2", with a 4 or so wire connection to it. My truck has a cover over all the heating ducts and that had to be removed first. If you have a cabin filter, it will be to the left of the filter.

You can tell if you have the right piece - as you move the heat control one way or the other, it will move.

Make sure your vent flap that this controls moves relatively easy (i.e. not jammed).