W212 Estate Rear LED Brake Lights & Brake Light Bar Stuck On

[dsharples]

Dear Forum Friends,
The rear brake lights on my 2014 S212 E300 Hybrid Estate have just begun staying on permanently whilst the ignition is on.
All other car functions, including 360 degree cameras, adaptive cruise etc., all appear to be working fine (so not a pedal switch or wet SAM?).
I've done some googling and can't seem to find anything that addresses this specific problem.
Does anyone have any knowledge, or at least where to check for any water ingress or anything else that could be related.
David.

 

[jc651]

I would be checking the peddle switch first.......... try taking it out or unplug it to see if the lights go out.

 

[dsharples]

I would be checking the peddle switch first.......... try taking it out or unplug it to see if the lights go out.

Would this be the hall effect sensor show in the red circle and inset in the diagram below (images taken from parts on ebay).
The E300 seems to have a number of sensors - probably for the hybrid/regenerative breaking?

 

[BlackC55]

if its plugged in to a diag machine you can see the live data. This will tell you if the BLS is turned on. If it is, then its probably a faulty switch.

 

[Justintyme]

if its plugged in to a diag machine you can see the live data. This will tell you if the BLS is turned on. If it is, then its probably a faulty switch.

I've just seen this thread, and you might be able to help Black55, have you any idea which cables and their location in the rear SAM ( I presume all the rear lights are fed from there?) for the 3rd brake light in the rear window, and the NR plate lights? Thanks in advance for your help.

 

[dsharples]

Just to confirm that I took my car to the local MB Dealer, who replaced a mildly waterlogged rear SAM, and I think a slightly submerged Towing Electronics Module, and rewired some corroded pins - and replaced some body grommets/vents to prevent recurrence. I rather wish I had checked the SAM first - as I'm not sure ALL of this **very costly** replacement work was required - when I suspect, due to the repair progress updates, and parts wait timings that were shared with me, a lot of drying-out and a few replaced connector pins would have fixed the problem in actuality.
But I also suspect that due to my car being a hybrid - so has the heavy duty power cables routed into the boot via the SAM, as that's where both the AGM and Auxiliary Batteries are - they were keen to keep all of the electronics perfect!