1992 Cadillac Fleetwood Broughman

It sounds to me the mechanism that trips your interior light on when your door is open may have come loose in the socket. If you look to the hinge area of your car you will see a plunger type mechanism that has a nut holding it to the body side of the door jamb. These often come loose and no longer work correctly unless you tighten the nut back up. They sometimes will break on the plastic part of the plunger switch and if it's close to the point of where it is to trip sometimes a bump in the road or anything that could cause it to shift will trip your interior lights. Usually these being loose or broken to the point your light comes on you will also get an audio signal or chime. After investigating these at all doors and don't feel this is what's causing it I would direct myself towards your headlamp switch. These are also known to get worn out and trigger your interior lights. You can sometimes get them to shut back off by turning the switch or by just wiggling it. And if your not getting the audio signal or chime this is more than likely your culprit. If your vehicle has the slide mechanism next to your headlamp switch that also controls your dash light dimmer and brightener this is where you want to direct your attention. None of these switches are terribly hard to replace. Good luck.