Adding Lights Wiring Diagrams - The square relay pinout shows how the relay socket is configured for wiring. This pinout image is only a 2-pole diagram for room on the page purposes, but you can get the picture here with this one since a 3-pole will just have 1 more set of contacts.. Relays generally have 4 pins (marked 85, 86, 30, 87) or 5 pins (85, 86, 30, 87, 87a). For most automotive relays, pins 85 and 86 are the coil circuit (and takes 12 Volts to activate the 'switch' - assuming a 12V rated relay, of course!)..