What's the mileage on yours?
Crackling noise might be a speaker but you never know.
There's a speaker in your door and there's a phone speaker on the inside of the plastic panel on the bottom where your feet rest. Look for the panel with a round "mesh-like" feel.
Also check fuses as per others suggested. There's a main fuse box under the hood on the driver's side.
And there's one inside on the side of the dash after you open the driver's door, secured by two big plastic screws. I usually use quarter to open it =)
Check all the fuses to make sure nothing is blown.
The brake pad light usually indicates worn brake pads. Check if you have "meat" left on them =)
BAS/ESP light might be a wheel speed sensor as others suggested or can bi trigger by the brake light switch module. If you want to ask how to replace it ask slk320chick =) She's the only girl I know of performing contortionist moves
By saying "Drives Funny", what do you mean? Is it pulling side to side or smth else?
Can be couple things: Tires need balancing, new alignment, I had to replace my steering drag link due to excessive play in it, might also be lower control arm bushings. When these go bad you start having problems with steering and the car pulls.
Also, make sure you don't have a leaking steering fluid hose. R170's are famous for it =) I replaced mine couple months ago or maybe a year ago and it started leaking again. Re-tightened clamps and the problem disappeared for now.
Low fluid will seriously damage your hydraulic steering mechanism. $$$$
If you are handy with tools I'd advise investing in some cheap OBII scanner tool which you can hook up to your phone. These usually cost under $20.
I got myself this one:
and use it with TorqueApp Pro on my Samsung Galaxy tab. It doesn't give you specific codes for roof, etc, but it gives you general codes and sometimes it comes really handy!