How to Use a Relay in Car Electronics


A relay is an electromagnetic switch. When power or ground is applied to a coil, the relay clicks on or off. The result is that a power wire to a function is either closed (connected) or opened (disconnected). When the line is connected, the function is turned on and works. When the line is disconnected, the function is turned off and will not work. A relay can be used on alarm systems to disable the starter, to flash the parking lights, and more.

Using a Relay to Flash Your Car's Lights

  • Read instructions that come with the alarm and relay.

  • Apply constant 12 volts to poles 85 and 87.

  • Put the lead from the alarm's output to pole 86. When negative pulse throws pole 86, poles 85 and 87 are already getting 12 volts. The switch is clicked and 12 volts are going from pole 87 to pole 30.

Using a Relay to Turn On an Amplifier

Using a Relay to Set Up Starter Kill With a Hidden Toggle Switch

  • Connect starter solenoid line to pole 87.

  • Connect poles 30 and 85 to 12 volt accessory line.

  • Connect toggle switch to pole 86 and ground the toggle switch.

  • Connect the positive from the battery through a fuse and flashing LED to the toggle switch.

  • Ground off of the battery.

Promoted By Zergnet


You May Also Like

  • What Is a Car Relay Switch?

    A car relay is an electromagnetic switch that allows a person to run a higher current application than that which would normally...

  • How to Wire an Automotive Relay

    Every circuit added to a modern car should be run through an automotive relay. The factory wiring in modern cars is light...

  • How to Install a Relay Switch

    Install Car Relays; How to Install a Relay Switch; X. Must See: Slide Shows. How to Install a Relay Switch. Four-pin relays...

  • How to Test a Car Relay

    A car relay is a particular kind of remote-control switch. It is magnetically operated and is used to control electrical circuits from...

  • How to Use SPDT Relay As SPST

    An SPDT relay refers to a Single Pull Double Throw electric or electronic switching device. SPDT relays allow electrical signals, digital or...

  • How to Know When a Car Relay Is Bad

    Whenever you operate a switch to an accessory in your car that carries a lot of current--such as the lights, wipers or...

  • How to Check Relays on Automobiles

    In order to check relays on cars, take out a good relay and replace it to see if the problem still exists....

  • How to Test Relays

    The relays in your car are electrical switches that are used to control different electrical components, such as the air conditioner, the...

  • How to Install a Car Alarm in a Car

    Have you recently purchased a security system for your car? Since there are so many different types of alarms it can be...

Related Searches

Read Article

How To Travel For Free With Reward Points

Is DIY in your DNA? Become part of our maker community.
Submit Your Work!