John Deere 445 won't start?

I had a hydraulic line burst on my JD 445. I replaced the hydraulic line. Since there was hydraulic fluid all over the underside of the tractor I pressure washed the mower after the repair was made.

The tractor was started multiple times after the repair/wash and it performed flawlessly while mowing for about 2 hours, until I turned it off and it wouldn't start again.

Now, when attempting to start the fuel pump does power up (the tell-tale whine is heard), all the dash lights power on as normal, the battery and its connections are all good, there is no click from the starter solenoid. My first thought was a problem with one of the safety switches getting wet but I used a jumper for the seat switch and that's not the problem. Not sure how to test the brake switch or the PTO switch. The starter was tested and worked fine. Any suggestions?