Well you're in luck because this is a pretty easy repair. You'll need a #10 torx driver to remove the drill housing screws. Once you've opened the housing, simply unclip the two lead wires from the old switch and slide them onto the new switch. Then close up the drill and you're done. You'll want to make sure that you've put the wires on the same switch terminals or the polarity will be reversed.

Let me know how it works out.