I was changing the bulbs on my 97 auto temp control and noticed the sensor was covered in a big dust ball. You know the the little grill on the auto temp control unit...on the right side of the unit...well behind that is where the senors is. I think removing the dust ball helped, you guy may want to do this if you have some time

 

something easier if you don't have time to take it apart is to buy some electronics cleaner (the air in a can) and just spray the hell out of it. save your brain and don't breathe it

 

i don't think that'll work...the dust ball is on there...i used the air-in-a-can before without taking it off and when i did take it off there was a big dust ball still