I have a john Deere Hydro 175. The PTO switch locked up and would not disengage. I bought and installed a new one. Everything seemed to work fine. A week later I went to start the tractor and nothing. As if there was no battery at all. The headlights work but it will not turn over. I crossed the solenoid and spun but did not turn over the engine. I disconnected the activator wire on the solenoid and it showed power when the clutch was down and I turned the key. I checked the (hot from the solenoid to the starter) and it showed no power with the clutch in and key engaged. What is wrong?