Gilly, you are the greatest and I thank you. Believe the problem is solved thanks to you. I went to the car, and checked the lights you suggested, including the trunk light. Well, it turns out that about a week ago, I removed the black plastic piece that fits inside the trunk at the back of the car and on top of the bottom of the opening. I was preparing to remove the back bumper of the car in order to install a new bumper strip. I still haven't done this, and have not reinstalled the part. Well, looking at the probe, it turns out that it was intended to press against the black plastic gizmo (non-tech talk) when the trunk was closed. Without the plastic stopper, the probe couldn't be depressed and the light couldn't be shut off! Talk about feeling a little sheepish! Thanks, again.
By the way, I wonder if you have ever removed the back bumper on one of these cars. I loosened the 6 nuts that hold the bumper on the back, but I am having difficulty getting the sides of the bumper detached at the back of the rear wheels. I am afraid to twist them too hard, for fear of breaking the now 11-year-old plastic. Do you happen to know how to detach the sides of the rear bumper? Thanks in advance for any ideas if you have the time to post. Again, I can't thank you enough for the help.