IcemanG17

Okay I have a brake pad sensor warning just about everytime I drive the car....whats weird is none of my sensors are ground down at all??

I think its is the drivers side rear wheel, since the CV boot popped at the track last time and spit grease everywhere...but after looking at a replacement sensor I can't see how that could cause the fault?

Is there an easy way to test for the bad sensor and the CE panel or somewhere? Or do I have to take the sensors off one at a time, then drive around to see which one is causing the fault?

Thanks

Mrmerlin

if you hav an old sensor just clip the wires off leave a bit at the car harness plug and solder them together then is simply plug and play at the connector junction blocks behind the wheels lots of fun if your working on the ground

IcemanG17

Stan
I was thinking of making one just like this....since it seems to be a standard plug type connector....so I was gonna solder one up to try it out!

Just so I understand right (challenge) the sensor "activates" when the circuit is completed right? So by the sensor getting worn down it completes the circuit and sets off the warining? Or is it the other way around, where it breaks the circuit?

IcemanG17

okay I looked in the wiring diagrams.......its odd that all of the front and rear sensors are wired together.....only two signals go to the "central informer" panel on the "black" side....they connect at plug 21/19 (from rear) and 17/20 (from front).....

Okay where is this panel and how do I find these plugs to see which one has a signal....hopefully its not the main CE board..... At least that way I can figure out if its a front or rear brake sensor...

Bill Ball

Brian:

It's just one big series loop. The central warning pin numbering is confusing. The loop just goes to pins 19 and 20 (numbers to the right of the wire). So, you can't isolate front from rear.

If the sensor heads are intact, then the likeliest problem is at the plugs behind the backing plate. These can be a bear to seat, and there are extra holes in the connector block that don't go to the harness. Pull the plugs and check each sensor for continuity. If all are good, jumper the harness plugs as a test (or just plug in your known good sensors). If that doesn't eliminate the warning, there is another connector (T19) in the circuit. If that is OK, test for continuity between the central warning plug pins 19 and 20. If they show continuity, then the warning box is at fault. Most likely you will find a broken sensor that looks good but has no continuity or a finicky plug that just needs to be seated better.

Bill Ball

Here's an annotated diagram.

IcemanG17

Bill
Where is the central warning control module at?? Is it built in to the warning light-ac switch-door lock panel under the stereo? Or is it somewhere else?

Okay so the circuit works when it is open......so when the sensor wears down or activates it breaks the circuit causing the fault....so just removing the sensor would cause a warning....I almost get it!! :>)

But of course putting a little jumper in the place of the sensor would solve the problem too...unless the warning panel is bad?

Bill Ball

The central informer, as it is called, is under the driver footrest.

david928

I broke one of the sensor wires while replacing the shocks, and the brake pad warning light became stuck on. Since I remove the wheels often and always check the pad thickness, I decided to splice the two wires together and bypass the warning sensor. This turned off the light. If you do this, just remember to pass along this information to the next owner, if you sell. One of these days I will go back and fix it correctly.

85fortheDrive

Ice, I gotta believe that Bill's diagram and spotting of the central wire junction can lead you to the promised land here. I'm assuming you didn't lose that little spring that keeps the sensor in place...? Bill may know but, if not, Alan will know how these things are electrically activated. That might also provide a clue.

I have a taillight warning light that comes on immediately after turning on the lights - every time. So I know the temptation to want to bypass the diagnostics. But the purist in me won't do it.

Good luck,
Tim

Bill Ball

Yeah, that bulb monitoring system....mine used to go off whenever it rained, even though all the lights were working. After going through the sockets very carefully cleaning them a few times, it stopped doing that. Maybe it's just not working anymore

nuc

I had the same problem your having with the warning light coming on everytime I drove the car, even with all new sensors.

I found the problem when R&Ring the axles. The passeger inboard boot had contacted the wiring harness which travels just above it ( the harnesses protective rubber grommet had split, allowing the harness to fall onto the boot) causing the insulation to wear through and ultimatley breaking the wire. Reconnected the correct wires (2 had broken) and no more brake warning light.

HTH

85fortheDrive

Dude,
Good catch there.

IcemanG17

Well I checked the harness that mounts the 4 sensors into 1 wire just forward of the brake booster...its in a circular holder with a tension mount (similar to the brake pad sensors at every brake)....there are two wires that plug into it with 2 wires each.....so I tried measuring the resistance of the wires....all came back fine around .2 ohms except for 1 that was 20 ohms...the bummer is I don't know which one it is!?!?!?!

I gotta bleed the brakes anyway...so when I get the car up & pull the wheels I will check the resistance of each sensor once I pull it from the car....that should be VERY telling.....they all should be quite low...one might be broke internally causing a spike and the warning light......

The only problems I can see is if all the sensors come back fine......then it has to be somewhere else in the wiring which will be a hassle!