Diesel tractor will not start. Cranks fast but no light on ignition. 12 volts gets to the ignition fuse when I turn the key.?

2016-07-12T13:43:20Z

What do I check next. Its a 5203 John Deere

guh2016-07-12T13:52:12Z

Only 12 volts? For a tractor...You need more then that!