Hi all just wanted to introduce myself and my new ride. Bought a 97 z3 2.8 a month ago and I absolutely love the car. 89000 miles and exceptional condition. I’ve been busy detailing every weekend and can’t wait for the weather here to warm up so I can take her for a drive. Ordered some parts from bimmerworld to bring the car back to top shape , just the usual control arm bushings (slight shimmy at 40mph) water pump , thermostat w/aluminum housing , new aluminum pulley and belt. I’m finding the information on this thread invaluable as I work on the car. I bought my wife a 2015 328i xdrive sportline 3 years ago and its a fantastic car to drive but it’s still under warranty and doesn’t need any work hence the new toy. While I have your attention maybe someone could enlighten me as to the purpose of one of the knobs on the dash. Check out attached pic.