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W-1-2-3 Go!
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Discussion Starter · #1 ·
Hello,

I recently replaced the front brake pads of my wife's 190E including new sensors. Went with Textars and everything went well, except one thing.

The pad sensor light turns on every time I step on the brake pedal, but I changed both sensors. Does it matter which pad I install the sensor on? I installed them on the inner pads if that matters.

Otherwise, where should I look? I can drive the car but I don't like the fact that it's still turning on even with new sensors.

Any advice is appreciated :thumbsup:
 

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'92 MB W201 2.3, '10 MB X164 GL550 4Matic, '14 MB W218 CLS550 4Matic
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913 Posts
The sensor insulation might be stripped at some point or it is bad
 

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1985 w201 Euro 2.3-16vlv / 1992 w201 2.6 Sportline Manual
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6,726 Posts
the brake pad sensors only complete a circuit. So if they touch metal they turn on. Go inspect ;)
 

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Discussion Starter · #4 ·
Would it still mean it's bad insulation if the light turns on only when I step on the brake?

I know they complete the circuit, that's why I'm baffled. The new pads were thick (Textar) and I installed everything properly.

Where should I look for the connections for the sensor wires inside the fender?
 

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Discussion Starter · #6 ·
did you install the sensor on the inside of the inside brake pad???



You know there are four brake pads right? The left outer and inner, and right outer and inner. So, yes, I installed them on the inner of the two brake pads for each wheel. And yes, I installed them the correct way. Otherwise I would not have been able to install the calipers back on right?

Should I have installed them on the outer of the two brake pads? I figured it should not matter...
 

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Discussion Starter · #8 ·
Nobody can confirm from experience whether installing the sensors on the outer pads is the right way or not?
 

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'01 SLK230,'93 190E 2.3, 1971 LS5 Corvette Convertible
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2,231 Posts
Mine go on when you step on the brakes and the roads are wet. Never bothered me enough to fix.
If you aren't going to use the sensors why not remove them so the light doesn't come on. You can inspect the pads when you rotate your tires like Logon_Bob and I use to do in the old days.;)
 

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'92 MB W201 2.3, '10 MB X164 GL550 4Matic, '14 MB W218 CLS550 4Matic
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913 Posts
The sensor insulation might be stripped at some point or it is bad
I repeat, The sensor insulation must be bad... in my W201 I took the sensors off because of the same symptoms and I keep checking the pads Old-School, by listening to braking friction when it happens and every six weks when I detail my wheels and clean the rotors

The sensing pin will complete the circuit if it gets wet

The sensor in my E320 (W210) are better designed as the sensing pin is covered with rubber and fully inserted in the pad so no wettness will give false alarms. Only real wear and exposed pin will complete the circuit

If sensors are a must, then I'm confirming that the installation should be in the inner pads as you don't want the snesor wires be any where near the rotor (common sense)
 

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Discussion Starter · #13 ·
The sensors should be installed on the inner pads.
Thanks for confirming. I sprayed the area with brake cleaner, but I'm sure it dried up quickly and would not cause any activation of the pad wear light.

If I wrap it with electric tape, (assuming it's the insulation) would that solve the problem? Or should I replace the wires as a whole?

I guess that depends on what the problem really is.

The pads in the wagon (300TE) are similarly designed and when I drive over water it does not trigger any pad sensor light.
 

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1981 300D
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646 Posts
I imagine the best solution for insulation would be to put a light dab brake silencer over the sensor, this way it would have some form of protection until it gets worn down by the friction. I used to have this problem the second time I replaced my front pads, but after 300 miles or so, wet or dry weather the issue went away.
 

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Discussion Starter · #15 ·
Hey Sean,

Nice to see you again, thanks for the tip. I'll consider that. No time yet to check the brakes, maybe this weekend. Hope you're doing well :)
 

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Discussion Starter · #16 ·
Just an update, drove the car today and noticed that the sensor light shows signs that something is rubbing the rotor (flickering as I step on the brake lightly)... will check this weekend.
 

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Discussion Starter · #17 ·
Thanks for your patience, it was the wiring contacting the rotor. My mechanic saw it, and played trial and error by disconnecting the plugs and making sure that did it, and it did.
:D
 
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