general problems of the 2007 BMW 5 Series

My problem started 2 years ago. After two days of very heavy rain I started my vehicle and my navigation screen started to flicker then eventually burned out over a two week time also my radio stopped working at the same time. I didn't have the 2,000 dollars to get it fixed. A few months later after several days of heavy rain I've noticed the drivers floor soaked then the car was hesitant to start. The car over another few months my wipers would cut on by themselves and I couldn't cut them off. It got to the point that I turned the car off and the wipers were still working with no key in the car. . . The car had to be towed to the mechanics. . Now my window work intermittently sometimes they work and sometimes they don't . . . At this time I also smell the odor of a burning electrical from time to time.

Not precisely sure what is causing this electrical problem, but all 3 occurrences of this problem have happened after I washed the vehicle and did not drive it. The electrical system is malfunctioning to the point it completely drains the vehicle's battery. After the second time I went to start the vehicle, I had the battery replaced. The 3rd time, all of the vehicle exterior lights had turned themselves on during the course of the night, and had almost fully discharged the battery. The car started, but many items in the electronic memory were lost, including date and time. The car involved is a 2007 BMW 528i, which I purchased 3 months ago, certified pre-owned.