temp/compass

Just purchased a 2001 1500 LT. I'm not too familiar with all the whistles and bells, but am trying study the manual. One thing I cannot figure out is how to calibrate/get rid of/whatever the temp/compass in the rear view mirror. With the "On Star" I couldn't find any buttons on the mirror that resembled the ones in the manual.
Also, do all Silverado 1500 LT's have positraction (or whatever it's called now)? Thanks - Bill