Re: GT20 PTO not kicking in
For a quick and dirty check, put a simple heavy duty on/off toggle switch where the pull out switch normally resides. Remember to either make a sketch of the position of each wire of take a few pictures so that you can put everything back correctly later. Then run a hot wire from either the battery or the amp gauge to one side of the switch (don't forget to include a fuse) and put the wire running to the PTO on the other side. It's the yellow wire I think, but back trace it to be sure. With the engine off, flip the switch and see if you hear the clutch "click" on. If it works, try using it for a while. If everything works, you can order a new switch or just rewire the toggle switch so that it uses the original power wire from the ignition switch. Also don't forget, until you restore switched power, the toggle switch will be "hot" all the time, and you might run the battery down if you're not careful and check it every time to ensure it's in the off position when you have finished with the tractor.
Thant's what I had to do to the GT, but unfortunately I haven't had time to rewire it back to switched power yet. It's working fine, but I have to remind myself to check it after I park the tractor.