Heat in a 1997 Toyota

[Omarj12780]

I have a 1997 Avalon that is driving me nuts. Currently, the temperature control for the heat will not go to the hot side. It blows out air just fine but it will not turn to get to the heat, so it only blows out cold air.

What could the culprit possibly be?

[Jigg007]

in the quietest of environments, and with the key to the RUN position without the engine started, so all accessories are on, move the temperature/thermostat dial and see if you can hear a whirring noise as a motor/servo moves a dampener door. If you do hear this, then you're probably low on coolant, which leaves none circulating to the heater core. Simply filling the coolant will cure this problem.

Should've asked, but most Avalons seem to have teh XLS climate control, which is the module with the 65-85 knob and push buttons, and is what i am describing as far as servos whirring.

[Omarj12780]

I refilled the coolant, but I am still having the same problem. It seems as if the knob is nor turning over to heat. I can turn the knob it seems like the know is broken. Are there any known problems with the knobs??