Why Brake Sensors Are Important
The beauty of modern cars is that they have a lot more technology built into them that allows the driver to be informed of what is happening with the car, at any given moment. One of the biggest benefits comes from knowing the status and condition of your brake system. This is important because the properly functioning brakes are the last thing that keeps you and your car safe in moments of sudden danger.
Enter brake sensors. Sure, they may not have always been your favorite feature of the car, and had a pesky habit of lighting up your dashboard on several occasions. But they did it for your safety. More importantly, that is the only thing they were designed for. The safety of knowing when your brakes are in need of maintenance before it's too late.
The traditional method of jacking up your car and removing your wheels one by one just to inspect your brake pads and brake rotors is tedious and not exactly convenient. Not every car is equipped with brake sensors, so to some this is still the only solution. For everyone else, this is the down and dirty on how brake sensors work.
The brake sensor is normally attached to the brake pad itself. Because brake rotors wear at a similar rate on the front two brake rotors, it's pretty common to only see one brake sensor. This is because if one side is wearing low, it's almost always the case that the other side is at the same wear thickness. The brake sensor itself is normally a wire that is encapsulated by a plastic compound. Once the compound wears down to what is considered a minimum wear level on the brake pads, the metal wire makes contact with the metal brake rotor, creating a light to display on the car's dash. This holds true for the rear brake pads and rotors, too.
Once your brake maintenance light triggers, you need to replace the brake sensor as they are only meant for one time use. Re-using old brake sensors that have already been triggered will not work even with new pads as they will always show your brakes need replacement, even if you just replaced the brake pads.