interior light remains on until car is locked

[southernstar]

For the last week, when I turn the key off and remove the keys from the ignition, the interior light/odometer remain on until the car is locked. In the past, of course, they would remain on for a brief period then shut off on their own. No, it is not the ignition switch (replaced mine about a month ago and the problem cropped up a few weeks after that). In addition, it doesn't matter whether the top is up or down, so I assume it is not a microswitch for the top.

Does anyone know what part is responsible for the time-delay on those lights, as I assume that is what is malfunctioning. Its no big deal and it forces me to lock the car at all times when I get out (not a bad thing), but I like everything operating perfectly and want to get it repaired.

Thanks

Brad