How to wire a relay

Relays are high-current switches that are controlled by a small switch or trigger. Relays allow you to use a low current device like a switch or computer to switch large currents like that of a headlight, pump, blower motors or heater.  In this article we show you how to wire a normally open 5-pin relay to control virtually any accessory.

View all of our: Automotive relays

Warning: Disconnect the negative terminal of the battery before beginning any installation

Download the wiring diagram: 12 volt relay wiring diagram

Pin configuration:

  • Pin 86 - Coil
  • Pin 85 - Coil
  • Pin 30 - Common Pin
  • Pin 87a - Normally closed pin
  • Pin 87 - Normally open pin

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