Windows, mirror adj., ext lights don't work

[Lagunae46]

Hey. I'm Ina market for a 35d x5. I have found a 2010 my but it has strange issues. While driving I noticed that turn signals don't work, neither does hazard lights. Then I wanted to open a window, none of the windows work. Then I wanted to adjust the external mirrors they don't work either. What is wrong ?? I'm thinking some kind of a body computer?? The battery was dead when we try to start it. Car runs pretty smoothly. Any ideas? Ohh and the external lights: headlamps are on all the time regardless of the switch position. Tail lights don't turn on even when I switch them to on( night driving would be an issue without tail lamps on) brake lights work though.