Mercedes Benz 190e - Speedometer/Odometer

Ever since I got my 190e (about a month ago), the speedometer has worked intermittently and the odometer has not worked at all; now, even the speedometer doesn't work.  I wouldn't be surprised if the PO loosened a cable or something to stop the mileage from racking up (but that's just the skeptic in me).  Is there anything I can access/check relatively easily?  I'd really like to avoid taking the dash apart and I'm still relatively new to all of this.