Brake pad causing "bulb out" indicator? - PeachParts Mercedes-Benz Forum

brookspw · #1 03-16-2004, 09:54 PM

My "bulb out" indicator was on so I dropped by the dealer. It was the license plate light, they even popped it in for me.

Well, the light didn't go out. The guy said, "put your foot on the brake". The somewhat flickering light became bright and steady when I did so.

He said that the cause of the light must be worn pads and / or a brake pad sensor.

Can anyone shed light on this for me?

manny · #2 03-16-2004, 10:38 PM

Are all your brakelight bulbs working & the correct wattage/make ?
Including the " high mounted " brakelight.

J.HIDALGO · #3 03-17-2004, 06:41 AM

Don't let the dealership take you for a ride...

brookspw · #4 03-17-2004, 08:22 AM

Quote:

Originally posted by manny
Are all your brakelight bulbs working & the correct wattage/make ?
Including the " high mounted " brakelight.

Yes, and they know I change the pads myself.

The bulb wattage/make should not be the problem, they are all the same and I have even changed them out serially with new ones. The only thing out was the license plate left bulb, which is now fixed.

It IS brake-related in some way -- the light changes characteristics when the brakes are depressed.

brookspw · #5 03-17-2004, 09:22 AM

Ok, more info.

I now notice that if I am completely stopped, and depress the brake pedal fully -- the light goes OUT. It is as if the sensor "makes contact" or whatever. IF I had a brake light of ANY kind out, there is NO reason that the indicator would go out if I depressed the brake pedal.

Maybe this is what the guy at the Benz dealer saw when he told me it was a brake pad/sensor deal.

Thoughts?

brookspw · #6 03-23-2004, 11:20 AM

Quote:

Originally posted by J.HIDALGO
Don't let the dealership take you for a ride...

UPDATE: Well, it was exactly what they said -- the brake pad sensors. Replaced the pads and sensors and,sure enough, the sensors were worn right through the "contact" portion.

Light is gone, now. It was not a loos brake light bulb -- I, too, suspected that but after checking -- eliminated that possibility.

Plus, with the new rotors and pads -- my ride is smooooooth.

G-Benz · #7 03-23-2004, 12:05 PM

Then that had to have been your brake pad wear indicator, not your "bulb out" indicator...

...the brake pad sensors cause the flickering as the pads wear until at some point it's solid when you depress fully at a stop. The bulb out indicator doesn't do this.

...but at least it's fixed.

Ali Al-Chalabi · #8 03-23-2004, 04:49 PM

If the brake pads were worn down through the sensors, did you change the brake pads as well as the sensors? Light is supposed to come on around 3mm of pad left and min pad spec is 2mm.

J.HIDALGO · #9 03-23-2004, 05:16 PM

Are you it was the "bulb out" indicator?
They may be side by side but they are NOT the same as you already know.

Gilly · #10 03-23-2004, 09:00 PM

I may have the answer.
On your 190E, the sockets for the warning indicators are all sort of "plugged in" to the rear of the cluster, they can be put back in out-of-order. If someone along the way had the cluster removed, like to replace bulbs for example, they may have inserted one in the wrong hole. There is a small number tag pasted to the individual bulb harness, near the socket, and a corresponding number on the back of the instrument cluster, this is one way to check it.
Maybe an easier way is to go back to the trunk and remove a bulb, I'd recommend just a taillight bulb. Then start the car and switch on the headlights, look and see if maybe a different warning light comes on (don't complicate things by stepping on the brakes, you just want to confirm proper operation of the bulb failure system).
I've seen this before.

Gilly

brookspw · #11 03-23-2004, 09:51 PM

Quote:

Originally posted by Ali Al-Chalabi
If the brake pads were worn down through the sensors, did you change the brake pads as well as the sensors? Light is supposed to come on around 3mm of pad left and min pad spec is 2mm.

I changed the pads, sensors and front rotors.