How to Wire a Relay

Video Transcript

"How to wire a car relay. This is a typical automotive twelve volt relay. It has spade style connecting pins on the bottom. Usually it will have the wiring schematic molded into the side. The pins that are referenced in this diagram are also molded on the bottoms next to the corresponding pins. The first thing you need to worry about is your power into the relay and that goes to pin thirty which is the pin that sits by itself over here. And we will hook up our power to that pin. Then we want to connect the item that we're going to be switching with the relay, whether that be fog lights or a stereo system or anything of that nature. And that gets connected to pin eighty seven. In this case, this relay has two pin eighty sevens, so you could actually hook a light up to either one. On occasion, a relay will have an eighty seven A, which is connected to the power in when the relay is off and the eighty seven is connected to the power in when the relay is on. So that's something to keep in mind. Lastly, we need to connect our ground which will go to pin eighty six. And the source from our switch, which a low current twelve volt source, and that goes to pin eighty five like so. And so when you turn this switch on, it will close the relay, allowing the power to flow from pin thirty to pin eighty seven and turn on whatever you have connected to it."