There are six (6) relays on the DT300i not counting the big, fat, heavy starter relay. You can easily identify five because the diagram shows the internal coil and switch contacts. The sixth one, in the upper left-hand corner of the diagram just says "oil contoller light." It MEANS, "oil light controller" which would mean relay. The oil pressure switch provides a ground to activate the relay coil. The contacts close and switch on the V+ to the oil light symbol on the display. All six relays are identical. All interchangeable. All can be replaced by auto parts store 12 volt relay and wire adapter.
