ABS/ETS finally FIXED!

[A1EK]

FIXED!
Well i think I have finally solved the problem with my ABS/ETS lights.
It seemed to be down to buying a replacement aftermarket brakeswitch
the whole time!!

I went to replaced the usual suspect brakeswitch about 6 weeks ago but
Mercedes at the time was closed for stock counting. So I went to
Eurocarparts to but the switch instead. The price was only about £3
cheaper (£9 instead of MB £12) so I thought there cant be much in it.
I fitted the Eurocarpart switch and without pressing the brake the
ABS/ETS light came on after 2 mins! I then noticed that when I pressed
the bake the brake lights only dimmed and did not go out? as if there
was a short. I checked the ratchet length of the brake switch plunger
and it was operating fine.
So back to Eurocarparts to get another switch and this time the bake
ligths went out when fitted, but 10mins later the ABS?ETS lights onthe
dash came on again!

I had noticed however that the ABS/ETS lights seemed to come on mainly
when I pressed the brake or shortly after, so one last try I went to
Mercedes and bought an original bake switch, and Voila so far no more
warning lights, for 3 days!!!

Moral is by Orignal parts when electrics are involved as Mercedes are very delicately balanced.

....and of course cruise, abs and traction are all back again too,
just in time for the snow!!

[mrwilliamsburg]

Congratulations! My E-Class has the same problem. Would you mind posting the DIY procedure for replacing the brake switch? Thanks.

[A1EK]

How to replace the Brake Switch REVISED as I have noticed there are nearly 2000 views on my original posting I thought I would improve it with some more photos.!)
mrwilliamsburg....
Please note that my car is a UK right hand drive model!

First you need to remove the underside panel of the drivers panelSee 4 photos with red arrows )
There should be 4 Phillips screws you need to undo first.

1 near the bonnet release.
2 near the front the opposite side to bonnet release.
3 underneath in middle
4 at the back above pedals.

With these screws removed you need to pull the tray towards you as there are clips on the front under steering wheel. Then near the centre console you need to pull downwards as there are 3 clips there also. That should be it! (Please note that I have added a photo showing the under try being pulled out which is on a left hand drive model, the steering wheel is also removed but obviously you dont need to do this!)

To remove the Brake Switch:
I found it best to put the seat right back and lie almost on your back on the floor. The switch is located above the brake pedal at the back. On the top of the brake switch in the 12 o'clock position, there is a little plastic catch, which you need to depress and then at the same time turn the switch clockwise a quarter of a turn. You may find it easier to unplug the two wires first. Once turned, you can remove the switch.
Pay attention to the length of the actuator (plunger),as it is on a ratchet system and your new switch needs to be the same length, otherwise it will not operatet properly.
Use an original Merc brake switch and just rotate the sitch anti-clockwise this time to fit back in the mounting.
Good luck, and I hope it fixes your car.!

[mrwilliamsburg]

Thanks so much! It worked!

[SF E420]

Thank you very much for these instructions. I have the same problem on my 97 E420. I will use your instructions and try and fix this problem.

[Raylee177]

Let it be known that I have also benefited from the instruction. Of course, it worked perfectly!

[Shipsake]

I have a 96 E300 Diesel and thought I might have had a lucky shot following your success but no. My abs/ets light will come on while driving or even come on when first starting the car - a couple times it would appear to come on after I pressed the brake pedal so I went to the dealer and bought the MB part and installed it per the manual. It seemed to help at first as went a week without any problems but that was just a coincidence. The abs/ets lights will come on, sometimes like today when they come on after a moment the speedometer also went to zero. This problem is absolutely the most aggrivating thing; what in Gods name would cause the speedometer to fail and be connected to the abs/ets systems - is it a wheel speed sensor? Anyone have this issue?

Alan

[blkE430sport]

I had the same problem, and thanks to your post it is now fixed. I didn't install the new switch (my shop did it), but after the new switch was installed the brake lights would flicker going down the street when not braking. I referred to your post, pulled the switch and adjusted the ratchet by pushing the switch in (all the way at first by mistake) then backing it out to the right length. That solved the problem. You can hear the ratchet click as you adjust. Just thought I'd post in case anyone else has flickering brake lights. THANKS for your post!!! It solved the ABS/ETS problem!

[blkE430sport]

One other quick note - on my 99 E430 Sport the plastic catch (that allows you to turn the brake switch 1/4 turn to remove) is located at 9 o'clock instead of 12 o'clock. No big deal.... different year, different location.

[badgs750]

I found this information helpful in fixing 98 E300 and thought I would share what I found with the old switch I took out. The contacts on the one side of the switch are badly pitted, there must be a bit of current going through that part of the switch. I attached a picture of the inside of the switch to show the part falure. I hope this helps the other people like me that want to understand what actually failed.