Do you mean they are not going off after you shut the car off and you are still sitting in it? My boss just asked me the same question because he was playing with the lights in his new Camry while waiting for someone. I don't know if there is an upper limit but if you don't open the door they'll stay on for a long time. After 30 seconds you should actually hear the relay or whatever it is click if you're sitting there but the lights will stay on. If you get out of the car they will go off after 30 seconds. I assume there's some sensor with the door but maybe there is one with the seat. I don't know what would happen if you open the door AND still stay in the seat. I haven't been curious enough to try that myself.