Possible faulty brake wear sensor?

Chasabi

Member
 West Yorkshire
Hi all,

My brake wear light came on last week. I knew the rear pads were getting low so I changed the pads. When I took the old pads out there was at least a third left so I don't think the sensor on the rear actually tripped. I changed the pads and the sensor anyway but the light is still on. Is there anything I have to do to get the light to go out? I've searched the forums and tried various combinations of key turns, leaving it for a minute, etc. It's been a week and the light is still on.

I can see the front pads have at least 50% of pad left so I don't imagine the front sensor has tripped. Could the sensor be faulty? It can't be the rear one as that is now a new sensor. Is there anything else that this light could mean?

This light..... Just in case there's any confusion regarding the light I am referring to :D

BrakeWear_zpsa8aa906f.png
 
For a tenner not a great loss.

It is a make contact, so any damage to the lead will trigger the light, either the front one or the rear one. Only one per axle.
 
£5.95 inc P&P for a quality Meyle part
Fitted a front one myself from them, 2 weeks ago. 5 minute job when the wheel is off.

http://www.ebay.co.uk/itm/BMW-E46-3-Series-Front-Brake-Pad-Wear-Sensor-German-Manufactured-34351164371-/390667021047?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5af591aaf7
 
Chasabi said:
Hi all,

I changed the pads and the sensor anyway but the light is still on.
BrakeWear_zpsa8aa906f.png

You have installed a new sensor.

If the pad warning light is on with the new sensor, the sensor connector is probably not plugged into the cars harness properly. I have made this mistake myself before.

It needs to push completely into the car plug so the lugs engage, it can take some force. Whip the wheel off and have a look at the connector.

If it is not plugged in properly, you get an open circuit which puts the pad warning light on the dash as if the pads have worn down and broken the wear sensor circuit, which is the designed behaviour.

If you do find it is plugged in properly, it must be a duff sensor. You can do a continuity test on with a multi meter. You should get continuity between the pins and close to 0 Ohm resistance.

if you don't have a meter, you could quickly plug in the old sensor and turn the ignition on which should put the light out. If so, use the old sensor and send the new one back for a refund as it is fcucked.
 
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