Brake pad sensor light

[P.Viby]

Well first of all a big hello to all again. Have not been here for a looooong time.

Well the car has been running great all summer and the new little smurf is having fun on the rear seat in a little baby seat.

But I am struggling with 2 VERY anoying things on the car. first thing is that my Brake pad sensor light wont go out, second is a problem with the PSE which I cant close anymore. But lets only deal with the brake pad sensor light here.

What is happening: Light remains on all the time.

What I have done: 2 new sensors in front, Tested with an ohm meter ALL sensors and they where fine. Tested loop from right front wheel to left front wheel. All with no problems.

When the car was on jacks suddenly the light was off we thought it was maybe just a plug then which where bad. We mounted the wheels on again took the car off jacks and it was fine. Thought we had fixed it and started to work on the PSE problem, when we where finish and started the car up again, light came on again :cursing: Saw the same thing in the beginning with light going on and off, often started off and then after a lilttle driving light came on. At that time I was sure it was becourse of the brakepads which where bad.

Have anybody had this problem or just a good idea what to do. Thinking about that the wire might be bad between the cluster and the brakesensors, but I have no idea where they go in and out.

Thanks for any input.

[Loren]

I would take the each sensor out the picture one at a time by unplugging the senor and using a jumper wire in it's place. I would do all four sensors this way - there is always a chance a rear sensor decided open. This should help narrow down the problem. If you have four jumpers in place and still get the light then you know the problem is in the wiring to the cluster.

[Tool Pants]

I have seen this before on the UK message boards and do not know the answer.

Brake light goes on, then off. All 4 pads are replaced and all 4 sensors are replaced. Then it happens all over again. Thought it had something to do with all the rain/water in the UK.

Asked Peter Smith about this issue and he has never seen it. Let us know if you figure it out.

[P.Viby]

Hey,

What more to wish for then 2 of the best guys helping me here, Loren and Tool pants thanks :notworthy:

I will try to ask my local dealer if he have some used sensors so I can make those "dummy" plugs. But I tried to ohm from left front wheel to right front wheel which means I then measure all wiring except the one going from the front wheels to the cluster.

Does any of you know where those wires goes in and out of car or if they end up in a connector somewhere before the cluster ?

Edited December 14, 2006 by P.Viby

[teeerex]

Hey,

What more to wish for then 2 of the best guys helping me here, Loren and Tool pants thanks :notworthy:

I will try to ask my local dealer if he have some used sensors so I can make those "dummy" plugs. But I tried to ohm from left front wheel to right front wheel which means I then measure all wiring except the one going from the front wheels to the cluster.

Does any of you know where those wires goes in and out of car or if they end up in a connector somewhere before the cluster ?

I thought the system worked in two ways - the first is indeed if you break the circuit by cutting(wearing away) the wire in the sensors completly - but the second which will happen first, is grounding the sensor wire to the vehicle ground - via the brake disc. This happens when the plastic coating gets rubbed off the wire. It is also the reason why if you change the pads immediately when you get the light, you can re-use the sensors (assuming they are not worn through) BUT as Tool Pants alludes to - once you have split the platic wire covering, any moisture/water will create a circuit to ground should they get wet - so you'll get false alarm readings.

So a continuity or low resistance test from the sensor plug sockets to venicle ground would also help you identify the problem (unplug them all first or a fault will show for all of them if there is a problem with just one ..)

Maybe this helps ?

Cheers,

Richard.

[Stefan]

Another thing to try is to wiggle each plug while someone watches the light. If the plug has condensation or isn't plugged in all the way it may not be making good contact.

[RayGT3]

Think about how these guys work, they are a small loop of wire encased in a phenolic type material. As the pad wears the sensor wears at the same rate and at some point the rotor wears through the wire loop and you get a light. BUT!!! if the sensor is flush against the face of the rotor itself, it will make the circuit and the light won't go on till the pads back away from the rotor surface. This would account for the seeming on/off of the light. I would guess in certain circumstances the light would go off when stepping on the brake and back on when the brake and pads return to the unengaged position. Just seems like a good explination as to what many might be experiencing.

[badawg99]

I had a problem with my brake light not going out. I checked the fuse and find that the 15 amp fuse was blown. Replaced it and light went out. Maybe this will help?

David B

[P.Viby]

Okay, a long time later....sorry.

But time to finish and close this topic.

For not making this answear to long here is the conclusion.

You can NOT use an ohmmeter to measure the brakesensors as long as they are installed. Reason why is that you might measure thru the disc and back. Meaning that you might be getting a good 0 ohm even the sensor is broken. What I did is that I went to my local dealer and he gave me some used sensors for free. I then cutted the sensors away and shorted the 2 wires from the connector. With that I just tried it on all the wheels and wupti 1 brakepadsensors where bad.

Good luck,

Pierre