Brake Pad Wear Indicator
![Brake Pad Wear Indicator](graphics/brake-pad-wear-indicator.jpg)
Electronic sensors provide a warning light for the driver when the brake pads have worn past a specified limit. They replace an audible metal clip that's fastened to the brake pad. When the pad wears down to the clip, a loud squeal is heard when the brakes are applied.
![Electric Brake Pad Wear Indicator Light](graphics/brake-pad-wear-indicator.png)
The electric pad warning system is a less intrusive way of indicating pad wear to the driver. When this wired circuit is interrupted, the pad wear warning light illuminates on the instrument panel.
![Use a multimeter's ohmmeter to test resistance.](graphics/multimeter.jpg)
Unfortunately, by the time the driver's light comes on, the sensor's circuit has already been broken, requiring sensor replacement. Test these sensors for resistance with an ohmmeter.
![Brake pads have grooves that act as a wear indicator](graphics/brake-pads.jpg)
Many brake pad manufacturers have cut a slot into the middle of the pad that acts as a wear indicator. The slot cools the pad surface as air passes through the groove. It also helps remove brake dust and allows gas to escape.