Volkswagen: seat warmer, dead battery, passat

Question
have a 2002 passat, used seat warmer last night, this morning the seat was still warm.  What controls the seat warmer?

Answer
There is a pair of roller switches on the dash in the center console.  I haven't checked the schematic, but the seat warmer should not stay on with the ignition off.  Otherwise you'd have a dead battery if you left it on.  Are you sure the car wasn't sitting with the sun shining directly on the seat?