2001 4 door coupe

My problem is electrical- the switch that directs air flow from the HC or the A/C condensor doesn't seem to respond whn you adjust the comfort temperature higher. i removed the switch/motor and checked- shore enough it doesnt turn in response to you turning the temperature control. Dear old Mom has a 2002, so i took the control set out of the dash, as well as the seemingly malfunctioning switch. i installed them in her car and they seem to work fine. so i am left with this- is there a temperature sensor that tells the switch how far for that switch gear to turn in order to get the desired comfort level? this has got to be faulty if there is one, but i cant seem to find it!