Originally Posted by toomany MBZ

Well, $20 is not much money, I think, for the cd-roms from mbusa.com

Which brake light are you referring to? The red one, parking brake on, and low fluid level, or the orange one, low brake pad wear indicator?
A/C, normal.
Engine not shutting off is a vacuum leak somewhere, or failed shut off valve.
Trunk opening, depends on the lock position, does it open any time with the drivers door unlocked? Spray some lubricant in the lock, and work the key back and forth.