After 11 years on Cheers, George Wendt is as comfortable a TV-room presence as an overstuffed armchair. Too bad his own vehicle, THE GEORGE WENDT SHOW (CBS, Wednesdays, 8-8:30 p.m.), strips the former Norm of any discernible personality traits. Ostensibly inspired by NPR's Boston-based Car Talk, Wendt's series -- about two grease-monkey siblings with an automotive-advice radio show -- is set in Madison, Wis., home of Whad'Ya Know?, another public-radio program that's much funnier than this CBS dud.