My understanding is (and I know it is this way on the smaller BX Kubotas as well as a some John Deeres and others) there is a series sequence of 'safety' switches between the "ignition" switch and the solenoid primary/trigger. Not sure how many on a given model. Getting continuity sequentially through all of those safety switches is required to trigger the solenoid. Given your circumstance in the remote bushes trying to solve such problems, I suggest this: 1) Locate the signal (12v) that you get from the 'ignition' switch only when you turn the key past the spring loaded position intended for Start. 2) Run a temporary wire from there to the solenoid trigger wire, thus bypassing all of the safeties. You might want to include a switch in that temporary wire to enable/disable the bypass. That should get you by until you have the tractor in the shop where you can get to the bottom of all the various interlock safeties, etc.