hi dave,
The heater switch is behind the three dials on your 205 heater panel. to get to it, you need to remove the actual dials. behind them you will see two screws, remove them then the three or four screws found on the heater switch.
Now the whole section will come off. remove the cables on the back and replace your switch.
Remember to take photos at each stage if your unsure.
have fun!
Mishal, July 2008