[MPerry]

On my 83 Cummins, completely mechanical engine, the overheat and low oil pressure are connected together with the fuel shutdown solenoid. If I recall a keyed hot connects to oil pressure switch, is passed to the temperature switch and then to the fuel shutdown solenoid. If pressure is high enough power goes to temp switch, if temp is low enough power opens fuel solenoid. On my dash is a over ride switch that provides power to the fuel shutdown solenoid while cranking and building oil pressure.