I own a 2000 626, and that has happened to me as well. I checked the light switch to make sure that it was in the door or off position( depending on what you prefer). Then closed the door. That worked for me. If that doesn't work for you than bring it back to the place that worked on your car. They may have had to remove another sensor and forgot to put it back. Their mistake not yours, so let then fix it. Good luck.