The old Big Cam Cummins engines built from about 1977 until the late 80's used a low pressure sender that was strong enough that it didn't need a relay. With electronic engines, the ECM reads the pressure sender and turns on the light and Buzzer. The buzzer came on at around 6 psi and it was simple to wire. I would think they sending units are still available because there are still a lot of mechanical engines in service. Kysor even made a shutdown unit that read oil pressure and water temp. They were popular with fleet and lease trucks. Kysor called it an alarmstat and they are still available.
Last edited by crenwelge; 10/06/2015 4:29 AM.
