If you want to disable the microswitch in the 2003 model, it is a little different than the descriptions above. After removing the plastic around the stereo etc., you will see two green wires that connect the microswitch to the circuit board. The microswitch is normally closed when the knob is NOT in the defrost position. When the knob is in the defrost position, the switch is in an open status. The easy solution is to solder a bridge between the two green wires. I put a picture of the exposed wires at
http://users.adelphia.net/~jrs99/images/ACMOD.jpg
Now I am in control of my AC!!!!