How Do Heated Car Seats Work?


Having a heated car seat in your car or truck is a great way to be warm during those cold winter months. The process behind heated car seats works just like a heated blanket. You will be able to control your heated car seat with the thermostat to ensure that you are not too cold or too hot.

The Resistor

A heated car seat has a heating coil underneath the seat cover. It is a long element of wire where electricity passes through. It is known as a resistor because the electricity is resisted when it flows through the coil. The resistance cause friction, which causes the seat to be warm.

The Relay

The Rostra seat heater will run on a relay switch. The relay switch is a mechanical trigger that allows for power to come to the seat. A relay will allow electricity to turn on the circuits. As soon as the relay is turned on, electricity will flow through the coil from the initial circuit. The circuit will not have a whole lot of power output and will only be used to make enough energy so that a magnetic field can form. As soon as a magnetic field is formed, it pulls a lever and turns on the relay switch. This allows the heated seats to receive power from the battery of the vehicle.


In order to prevent the car seats from overheating, a thermostat is placed inside the cover. If the heating coil does not have a thermostat, it will run indefinitely. Overheating can cause damage to the car, fire, and injury. The thermostat monitors the heat output and will turn the relay power off when the desired temperature is reached. When the seats start to cool down and get colder than what the thermostat says, the thermostat will call for the switch to be turned on the heated seats allowing the heat to flow again. The thermostat will also control the low and high settings on car seats. There should be buttons on the steering wheel or on the seat bracket that will allow the user to control the levels of the thermostat. This will also allow a person to turn the system on or off.

Purchasing Heated Car Seat Covers

If your vehicle does not have heated seats, you can purchase a heated car seat cover. A heated car seat cover has an adjustable strap that is designed to fit even the most irregularly shaped car seats. The car seat cover does not require any invasive installation. It will simply plug into the 12-volt adapter already in your vehicle and allow you to have heat within your seats.