There are 2 screws on the back of the handle. Remove those. There are 2 screws next to where the wire goes into the unit. Remove those. The neck and handle will slide off as one piece. The switch is a simple rocker switch on the back of the unit and you can remove it with a little pry form a screwdriver. It is a simple switch you can get for a couple dollars at Lowe's. Take the switch with you to get the correct size.
Murfdogger
June 2006