I have a 2000 S430. We have had a lot of rain over the last week. Last week, while I was driving back from work, I happened to drive the car through a large area of the road with standing water. Following morning, I had coffee mug sitting on the middle front armrest which spilled all over the front passenger seat and possibly the back floor section when I was trying to get in the car. Well, instantly as I started the car to drive off, I got the trunk open error. I stopped by the independent service center on my way to work, and he said its probably because your water catch reservoir is clogged and has caused the water to get in the car. He showed me where the water was overflowing in that reservoir, he was finally able to drain it. He advised me to have the front and back floors vacuumed to remove any water, which I did. The back area was really not that wet. Now, the backlights stay on even when I turn the car off and end up draining the battery. What is your advice?