Wear sensor

[motorsport]

I have a 95 318i. Recently, the brake lining light went on, so i replaced the front and rear pads they were both pretty bad. To my dismay, when i was on the rear left wheel the wear sensor and all signs of wiring were missing from that wheel! Obviously, the light is still on on the dash. I figure i'll have to get a new wear sensor and what not. Has anyone else had their wear sensor disappear, and what did you do about it? thanx

[1996 328ti]

You do know there is only one sensor in the front and one in the rear?

[ClubSport]

The sensors are on the front left and the right rear, not on every wheel. You need a new sensor up front to make the light go off. Once a sensor is triggered, it stays triggered, it's no good anymore. You can actually see how it gets crushed to complete the circuit.

[motorsport]

well why is the warning light on on the dash?

[1996 328ti]

Is it the brake wear warning or brake fluid? I think there are two different warning lights.

[motorsport]

it is definately the warning light for lining wear.

[schussey]

kinda confusing....does the sensor not just have to be replaced?

[ClubSport]

Yes! The sensor has to be replaced!

If your light is still on, then it's not plugged in right, or the rear sensor has been triggered, and IT needs replacing.

[schussey]

yea thats what I thought had to be done...


oh and btw, whats up dan (motorsport).

[motorsport]

thanks CHRIS/schussey now everyone knows my secret identity, yea im gonna get the wear sensor soon. Should i go ahead and do front and rear sense i dont have a scan tool to see which has been triggered

[ClubSport]

You can look at the sensor to see if it has been triggered. When the brake pad gets really thin, this allows the sensor to be permanently crushed between the rotor and the pad backing plate, completing an electrical circuit inside the sensor probe. That's why simply replacing the pads won't turn off the light.

The sensor's probe is made of copper, or some metal softer than the rotor, so it won't scar the rotor. My front sensor was triggered, and you could tell where it had been rubbing on the rotor. At $21 apiece, I'd find out which one it was before buying 2 of them.

[atompson]

My ABS light is on. Is that the wear sensor or is it something else?

[1996 328ti]

Something else.

[ClubSport]

My ABS light is on. Is that the wear sensor or is it something else?

Maybe wheel speed sensors.

[Jeff Spooner]

you guys are killing me. The sensor wire is just that, a piece of wire. When the pad gets to thin it wears though the sensor and cuts the wire, thus leaving an open circuit not completing one. There are a lot of reasons the abs light could be on. Get it scanned.