JD4600 intermittent start problems

[Cedar Brook Forest]

I have a 2006 JD 4600 utility tractor. I’ve been having intermittent starting problems and they seem to be getting worse. Sometimes I’ll turn the key and they’ll start right up. Sometimes I’ll turn the key and it will just click once. When I turn the key again, complete silence. if I disconnect the battery and reconnect it the click will come back for one key turn. I’ve changed the key switch fuse, and the start relay fuse. Doesn’t seem to change anything. Any help would be greatly appreciated.