On most of the fire and rescue trucks I have worked on, the pump injector pump solenoid on the engine is powered through a relay. You turn on the ignition switch or key and a relay supplied power to the injector pump. Turn key or switch off and relay opens and injector pump shuts down fuel and engine shuts down. You might also have a screw that can override the electrical side of things and get it running.
2014 Coachmen Pursuit 31BDP
2016 Ford C-Max Energi
1987 Chrysler LeBaron Convertible
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