Welcome to the forum! You're gonna love it here
The little slider thingy is a Bass Amp control. To the right, more bass, to the left, less bass. The amp for it is under the center console forward of the shifter in my car.
If you can't tell the difference (It'* not REALLY obvious), the amp may be out. Junkyard part!
As far as the driver information center, mine doesn't track oil changes, etc., but it does everything else including dispense beer. Are you talking about the 2002?
Anyway, try disconnecting your battery for about 30 minutes. It should clear the memory. Then reset the clock and all your presets, and cal the compass! We can help you with that, too.
Definitely try to get an owners manual for your car. Either from the dealer or off Ebay. Also, fill out your signature in your profile so we know what you drive! It'll make future replies alot easier for us, cuz we forget who'* got what with almost 300 members! (Think of it as bragging rights!)
Again, welcome! Glad to have you