brake pad wear sensor 1999 323is

[davec1957]

I've got a defective brake pad wear sensor (the pads are in excellent shape) on my 1999 323is. Can I shut off the "pad wear" dash light by merely disconnecting the offending sensor? I realize a new sensor is only about 15 bucks but I'd like to shut off the idiot light while I wait to make a trip to the parts department.
-Dave

[Manolito]

That should work just fine.

Note that the sensor itself is unlikely to fail unless it is hit by a foreign object. The more common failure is a wire blowing in the air beneath your car that has chaffed insulation and has shorted out against the rear suspension. You might be able to fix it with some electrical tape if you can find the bad spot in the wire.

[davec1957]

Thanks for the info. Am I correct in assuming that a circuit is broken when these sensors either break or get worn down as the pads wear? If this is the case, is the sensor wire actually two wires that need to be connected (or soldered) in order to re-establish continuity if the ceramic portion breaks?

[Manolito]

I believe that there is a single wire to the sensor. When the rotor touches the sensor, it wears through the plastic and grounds the metal contact inside. That ground signal illuminates the light. Actually, there is some logic in there that keeps the light lit even if the ground signal is occasional.

[Jeron]

I'm pretty sure its two wires and when the rotor wears away the tip of the sensor it breaks the connection. You could try simply connecting the wires but I dont know if it is looking for a specific resistance or simply a connection.

[davec1957]

Here's the story with the brake wear sensor: Although it appears to be a single wire, the sensor is actually connected to the main wiring harness by two paired wires. When the pads wear thin and the rotor cuts the tip of the sensor, an open circuit is created and this causes the idiot light to activate. All that was necessary to eliminate the idiot light was to cut the end of the sensor off, remove an inch of insulation from the paired-wire, twist the two wires together (soldering would probably be a good idea if it's a permanent solution), wrap with electrical tape and tuck the wires up out of the way. To kill the idiot light you then have to turn the ignition key to "on" and wait a minute or so for the light to go out.

Anyone who regularly maintains their vehicles probably has no use for a brake pad wear sensor - I'll replace my pads long before that sensor would detect a problem.

[coolbear1]

It is two wires, and the price for the sensor is rediculous.
I don't recomend this, but, you can easily cut the wire on the old sensor and put a temporary wire nut on it.

I, by no means, recommend this to anyone.

[dgreenbmw]

great post dave. coolbear1: good tip.