John deer f 930 clutch will not stay engaged unless you hold it

Check the following break switch first, then the seat switch, if that doesn't fix it take apart the main wiring harness under the panel with the ignition switch. Clean the harness well; I used contact cleaner, while it's apart put some dielectric grease on the connections.

If that still doesn't work, follow the wire from the electromagnet that holds the PTO lever in the engaged position, if you check the voltage with a voltmeter it should be 12v (don't remember the amps but it's low). You can also check to see if your electromagnet is bad using a cheap old 9v battery you probably have laying around. With the weak 9v battery it should just hold the lever in position briefly if you're not holding the lever. If not the electromagnet is most likely bad. Worst case scenario is you can wire in a switch to provide power to the electromagnet, but shouldn't need to do that. The connection to the electromagnet is
"Weather Pack Environmentally Sealed Connectors" made by Delphi Packard. There are several places you can get the connectors including amazon if you would prefer not to modify the factory connections.