How Remote Car Starters Work

Viper 7251V 2-Way LE Responder Remote

Crimestopper RS-4 Remote Car Start with Keyless entry, Data Port, Turbo timer, Gas and Diesel

During the blazing hot dog-days of summer, or the bone-chilling cold of winter, remote car starters work wonders for making your car comfortable. Without one, in the winter you have to bundle up to rush outside into the arctic blast of a cold-winter day, fumble with your keys as your hands go numb to unlock your door, and try to pry open your frozen door. Your teeth chatter as you start your car, then you rush back inside where it’s warm while you wait for the car to warm up. But if you have installed a remote car starter, you push a button from inside where it is warm and cozy, and wait in comfort till you are ready to get into a warm, defrosted vehicle. But how do remote car starters work?

Remote car starters bypass the ignition switch, essentially allowing a control unit to “hotwire” the car to start by remote control. Several components must be installed and work together to make this possible.

The common components in remote car starters are:

  • Transmitters- the key fobs that have the remote buttons.
  • Receiver- the control unit that is installed in the car, generally under the dashboard.
  • Relay set- controlled by the receiver, to handle the connections to bypass the ignition switch.
  • Hood Safety Switch: If the hood is open, the remote car starter is disabled to prevent injury when someone is working or checking fluids.
  • Wiring Components: Fuses, wiring connectors, antennas, zip ties, and other installation items.

Also, for many modern cars with anti-theft, you must purchase a separate kit specific to your make and model of car to bypass the anti-theft feature that prevents your car from starting if it were “hotwired”.

As a safety feature, remote starters cannot be installed in manual transmission vehicles. There’s not a reliable way for the control unit to verify the vehicle is not in gear. The last thing you’d want is to try to start your vehicle, and watch it take off with no one driving.

The transmitter is a miniature radio device that transmits an encoded signal telling the car to start. The antenna installed inside the car receives the signal, and carries it to the control unit. The control unit compares the encoded signal and verifies that the signal is from you. You wouldn’t want a thief or a neighbor to be able to start your vehicle! Once the signal is verified, the control unit blinks the parking lights on your car so that you can see the command was received.

The control unit activates the relays to bypass the ignition switch to turn on the systems that run the engine, essentially as if you turned the key to the run position. If there’s an anti-theft feature, it will activate the installed kit to send the correct “password” to the car to allow it to start. The control unit activates another relay, engaging the starter.

The control unit monitors to see if the engine starts- usually by monitoring the engine RPM signal, or by seeing the alternator charging the vehicle. If it doesn’t start in a few seconds, the remote start will stop cranking the starter, wait for a few seconds, and try again.

Once the engine is running, the car turns on the parking lights to show you that the vehicle is running. The remote starter actuates more relays to turn on all your vehicle’s accessories such as your wipers and blower motor.

The car will continue to run until either the timer expires which is generally set for 15 minutes, you press the stop button on a transmitter, or until you hit the brake pedal. To keep the car from shutting off when you get in, you put in the key, and turn it to the run position before hitting the brake. The car will drive normally after that, and will shut off when you turn off the key.

Remote car starters also come with several variations and options. There are integrated car alarms, and options for remote locking and unlocking of doors, or to pop your trunk.

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