The "Check Brakes" light on your BMW 325 is a special warning light that indicates when your brake lights have failed. Resistance is measured in the bulb filament, and a signal is sent to the brake warning light when the bulb burns out. The indicator light, located on the dash, uses a miniature picture of a car with a small light at the back of the car showing the brake light failure. Once you have replaced the bulb, you must reset the brake warning light.
Remove the fuse panel cover in your BMW 325. Underneath the cover you will see a large, round, open port that will accept a pinned connector. This is the diagnostic input.
Plug the diagnostic reset tool into the port on the fuse panel.
Turn the ignition key to the "II" position, and wait for the flashing light on the reset tool to stop blinking. When it does, the brake warning light will go out.
