Any time you have a lot of current that has to be switched by a small amount of current, you have a BMW Relay to do the job. An example: Your headlights require a lot of electricity to operate. If all the electricity required to run your headlights was actually switched on and off by your headlight switch, it would have to be extremely robust. Plus you’d have an increased risk of shock. So instead, your headlight switch sends a small signal to the headlight relay under your hood, which then switches the high current that operates your headlights.

A BMW relay is used on most of the high-current motors and devices on your vehicle, like the sunroof motor, horns, and air conditioning. A relay is basically just an electrical switch, and they’re used all the time in our cars and homes. So the next time you’re sitting in your car with wet feet and you turn on your headlights, thank your BMW relay for keeping you from getting juiced by a hundred amps of electricity!