The solenoid screws into the back side of your injector pump. It has one spade connector that carries 12 vdc and the body of the solenoid is ground. The pictures below are my tractor, but yours is similar in location.
Failure of the actual solenoid is rare, but you can test for 12 vdc at the wire when you are trying to start. Most often, there is a problem with the seat switch and the operator present system is keeping the solenoid off. Most times a seat switch can be bypassed by setting the parking brake. You can also jumper 12 vdc to the solenoid. But if the tractor starts, you'll have to pull the jumper before the engine will shut off. You can also remove the solenoid from the injector pump since that does the same thing as applying 12 vdc, but your tractor will not have any way to stop the engine if the solenoid is removed. It's spring loaded plunger has to press on a lever inside the pump to shut off fuel flow. It's designed to be failsafe so that it keeps the tractor shut off anytime power is removed from the circuit.
