Welcome to the forum Hurshi.
My guess is the howling sound is your tires, OR seeing as you just got this car I would drain and replace the diff fluid just in case. The knock when you change gears is probably a worn out rear shaft coupling, OR it could be any of the number of bushings in the rear so get the car up on a machine and have a good look at all the links and subframe mounts. If your heat is not turning of you may have a vacuum leak, OR check this thread out..Only heat coming out of the vents 190E 2.3
The LCD display does not control the inside temperature of the car.
Check your fuses for the short and see if any of them blew. Also check the fuse(s) on your OVP relay, red relay located behind the plastic behind the battery.