Electronic climate control

I own a 1993 Pontiac Bonneville SSEi that has electronic climate control.
Sometimes it works and sometimes it doesn't. It has a button that when pressed is supposed to show the outside air temperature. Sometimes it doesn't show any temperature at all. (That's when the climate control seems to work.) And sometimes it shows -37 deg F. Thats when the heat blasts uncontrollably. There must be an external air temperature sensor somewhere but I can't seem to find it. Can anybody shed some light on this. Any info would be greatly appreciated.Car Repair Talk's forum.