Heat/Air Conditioner Setting Knob
 

The knob to regulate the fan for heat and air conditioning only works at full blast now. I need to replace the switch but wonder if anyone has advice on how to remove the knob without causing damage.

Heat/Air Conditioner Setting Knob
 

Kind of late since you posted awhile ago, but the knob just pulls off. You have to wiggle it a bit, but it will come off.

Before you go replacing the switch, check the resistor body . That is in the circuit for all speeds except hi which is controlled by a separate relay.