BMW: brake light sensor

In article <1qw3b.12993$bellglobal.com>,
Terry <ca> wrote: 
 

How long ago did you do this? The warning light has to be re-set by
turning on the ignition but not starting the engine and waiting a few
minutes. It *will* go out eventually if you don't do this, but can take
some time.

You did also check the sensors front and back?

--
*Men are from Earth, women are from Earth. Deal with it.

Dave Plowman co.uk London SW 12
RIP Acorn

Check the wire to the wear sensor on the two wheels. Sometimes the thin
wire can get severed by the disc rotor if it isn't installed properly. It
can be joined up again or replaced.

Steve

"terry" <com> wrote in message
news:bim30g$b9g$btinternet.com... 
cause 

If it's like my '94 325i, its the brake light switch. Relatively easy to
replace yourself. See archives or do an online search for "BMW brake light
switch". There are instructions on some Bimmer websites on how to replace
the switch.
Greg

terry wrote in message ... 

You also need to replace the sensors at the wheel(s). They are what
detect wear and send it to the dash light. There are always 2 sets, one
in the front and one in the rear, on diagonally opposed wheels, usually
drivers side front/passenger side rear.

If the light came on and you did the brake work and didn't change the
sensors, the light will still be on. They are basically just little
metal loops which extend into the pad media. As the pads wear down so
does the loop. When it wears down enough to wear through the loop, the
open circuit causes the light to go on.

This is one of the most asked brake service questions, and there are
lots of model specific sites you can find for more information if you
need it.

Cheers


terry wrote: 

Once again there seems to be confusion between the brake lining sensor
indicator and the brake light switch. The lining sensor senses the wear
on the brake pads. The other one checks for burned out brake light bulbs
or faults in the circuit.

I've already posted on the wear sensors.

As for the brake light indicator, besides the usual stuff like bad
circuits and burned out bulbs, you might also want to replace ALL THE
BULBS WITH NEW ONES. I've been told (and proven to myself), that having
a mix of old and new bulbs in the circuit could cause enough electrical
variance in the circuit that the check light will come on. Sounds odd
but it has proven to be the cure in some cases.



singteck wrote: 

In article <RVJ3b.3677$cgocable.net>,
Stan Peterson <net> wrote: 

Sounds like a coincidence to me - the parameters of a bulb that might
effect a warning circuit don't change throughout its life. More likely
simply changing the bulb cleaned the contacts. That's assuming they were
the correct bulbs in the first place - the US seems to have a variety not
available elsewhere.

--
*I don't have a license to kill, but I do have a learner's permit.

Dave Plowman co.uk London SW 12
RIP Acorn

There is a small sensor on one of the front tires, and the diagonal back
tire. This sensor has an appearance similar to a fuse, when the pads wear
down, the band breaks and the light turns on. You need to replace one or
both of these sensors.



"terry" <com> wrote in message
news:bim30g$b9g$btinternet.com... 
cause 

In article <supernews.com>,
Jeff Strickland <com> wrote: 

The 'band' doesn't have to break - although it will if you continue to
drive after it comes on - it merely has to make contact with the disk. The
band or loop is there to prove the circuit - a single brush contact would
do the same job but would not necessarily show up a fault condition.

--
*Verbs HAS to agree with their subjects *

Dave Plowman co.uk London SW 12
RIP Acorn