Welcome to JA!
I would start at the start switch and go out from there.
to check the range shift switch
check for power in if switch is working there will be power in and power out
if not working there will only be power in
also common problom is a poor ground.
Let me know if i can help more!
Let me do some checking to see if there is any non copy right links to help on this.
Can i get the vin on your tractor.
I have some hits on a good manual with the electoral but there needing the vin info,
Thank you !
Here is a link for a detailed service manual.