1991 Jaguar XJ6 • 6 cylinder • 110,000 miles

When I turn on the heater or switch from a/c to heat there is a banging noise coming from under the dash. It seems like the "door" that needs to open or close to allow the heat to come on is getting stuck. The banging seems to be the door trying to switch from a/c to heat is flapping. Could that be?
January 20, 2011.

Yes, that is the most likely problem. You need to identify where the noise is coming from and check the vent door and repair as needed.