aircon illumination?

my air con and heater display bulb has not worked for some time,but during one of the coldest nights we had that winter i got into the car only to find that it was illuminated but soon went out again when the car heated up thus telling me that it aint the bulb but a loose wire or connection maybe.Hopefully someone has had the same problem and can tell me whats up and how to fix it.

young dave
May 2010