First you must remove the top cover by sliding the top backward after removing the two screws on the back.
The main dial must also be removed (just pull firmly outward (unclips) The face panel can then be removed (you can see the clips now the top is off, be carefull they are a pain!!) once off the timmer dial can be pulled off revealing the two screws which hold your timer on. The rest is easy ish..... Ps don't forget where each wire goes...
Daryl watkins, April 2009