I have a ZD321 mower and it will not start at all or turn over. It just cut off while mowing and won't do anything. Glow Plug light not on. Checked all the safety switches and all were fine but I changed them all out anyway. Checked relays, starter, battery power, and battery terminals. What else can I try? Service Tech said it would be 4 weeks or longer before they can look at it.
How did you check, with a volt meter/VOM? What did you do to check the starter if the mower won't even turn over?
If you checked the battery and had at least 12.4 volts, and if you have any other electrical device (hour meter? lights?) that works, the next thing to check would be the amperage of the battery (load test it), which you can done at one of the big auto parts stores.
If the battery has enough power that it should start the mower, the problem may be in your wiring (a hidden break, or a connector that seems tight but doesn't make an electrical circuit)... or it may be in your starter itself.
If you narrow it down to the starter, you should read
this thread about my mishap, and all the great advice I got.
Best wishes for a quick diagnosis, and keep us posted on your progress!