Givemeabreak01

Need assistance on how to reset the “Brake Wear” Light after replacing pads & rotors all around. Thank you.

Rudeney

Assuming you have replaced the worn brake pads, you also need to replace the wear sensors on the pads. There will be on on the front, and one on the rear.

Givemeabreak01

Rodney,

I might need a lesson on what "triggers" the Front and/or the Rear Brake Wear Sensor to activate the electrical circuit to turn on the Instrument Cluster Message Light, i.e., "Brake Wear." While the Rear Pads were close to being thin enough to break the wall of the cavity the sensor probe rides in, there was still material on the pad, and that cavity wall was NOT broken. Plus the Front Pads had even more thickness of pad remaining than the Rears. Accordingly, I didn't believe new sensors were required, and DID NOT replace them. Are you saying that my light is still on because that one or both of these sensors is indeed bad / faulty? Should those sensors be replaced with EVERY pad replacement, regardless? My limited knowledge of the system told my "brain" that the pad wall of the sensor cavity had to be broken and the sensor required to make contact with a turning rotor to "trigger" the light. Thanks for any clarification you might provide us on this system. I certainly will "jack it up" and replace both sensors if you believe that to be what's keeping my light on. Thanks again, Ed V (givemeabreak0l)

Kustom1911

Rudney is correct, replace the pad sensors is easiest. W209 pad sensors have 2 wires in each, they are monitored all the time, so any interruption in the signal throws the code.

They are not expensive, but if you wanted to take the time you could do a ohms test to find which 1 or both have no signal.

Rudeney

You have the "two conductor" sensors. These use a loop of wire that makes a continuous circuit. If the wire is broken, it will trigger the brake wear light. If the wires in the sensor go to ground, the light will also trigger. If your brake wear light is illuminated and yo have replaced pads, then you also need to replace the sensors. I once had one that was defective and would trigger the message in the rain. Replacing it solved the problem.

Givemeabreak01

Thanks to Rodney and Kustom 1911 for replying to my post concerning Warning Light / Brake Sensors on our 2008 CLK 350. I did buy two Sensors from the dealer and took the wheels off the hubs and pulled the front sensor out and replaced it. Put that wheel back on and checked the light and it was "Out." Put everything back together and now have a New Sensor left to wait for the next needed Brake Job. Thanks again to you both. Lesson learned for me. Next time it will indeed be easier to just replace both sensors for a "Complete" Brake Job to avoid the hassle of having to "do everything twice."

Rudeney

Glad to hear it's fixed! In the future, if you don't wear the pads down to the sensors, you can reuse them. Also, you may find that the pad that get the most wear is not the one the factory installed the sensors on. You can move the sensor to a different pad (inner/outer on that same wheel) if needed.