My '99 Tahoe has the same issue with interior lights coming on any time they please. I replaced the headlamp switch described in the previous reply, ok for a short time then they acted up again. Was told I needed to replace the control module under the dash that controls the locks, window switches, lights, etc. which I did ($200.00) and that worked for about 10 days. I looked at the switch for the rear hatch and the "O" ring was shot and I thought water might be getting into the switch and making the connection so I replaced that and let it sit inside for a day or two and then one afternoon the lights were on again. I would be interested if your headlamp switch replacement works, maybe I just got bad one? In any case over-riding the interior lamps works but you always have a dark car to enter and like anything else you pay for the lights they should work when you need them. Any other suggestions are appreciated.