The diagrams and photos show how to wire up the fuel pump and oil-pressure switch to a commonly available, industry standard, ISO-type "1 Form C single pole/double throw" (SPDT) relay.

It has 2 terminals and 4 connectors and you can look at the DPDT relay as the equivalent of 2 Single Pole Double Throw SPDT relays. DPDT relay applications 1. Change motor direction with DPDT relay As ...