Sorry - I took a closer look. Its only the rear passenger doors courtesy lights that are staying on (along with the rear cabin lights) and I think I have narrowed down the problem. On the front doors, when you push in door switch (as if the door has closed), you can hear the switch(sensor?) click. When you do this with either rear door, you don't hear the click. So there must be a separate sensor (underneath the hood?) for just the 2 rear doors that is out. But I did check my muffler bearings and they are OK. Thanks