The switch is installed in the door latch assembly inside of both front doors. It actually comes out with a quarter turn and disconnecting the wire harness. There isn't really anything to keep it from coming out without removing the latch assembly from the door, but I couldn't get a good enough grip on the switch to turn it out. It is in a weird spot at an angle off of the latch so you have to contort your arm up inside the door. The latches aren't hard to remove, it is just a PITA to work inside the door. I don't remember the switches themselves being very expensive. I replaced mine about two years ago and have not had a problem with the door ajar light since.