Ml350 2010 4 matic diesel. Rain Water Leak

[pikeface999]

Firstly can I say I have spent hours and hours reading threads regarding water leaks on ml350 2010,s and have not solved my problem. I do not have a sun roof.

After some very heavy rain a couple of days ago I had some electrical problems which I assume are water related . There is water in my battery box so I assume the SAM has water in it. All carpets are bone dry on top, underneath close to battery box faint traces of water. When I drove the car I could hear water sloshing in the back of the car.
I have stripped out the boot and there is definitely some water in the tyre well, but for the first time I lifted the 2 white covers identified with the red circles in the photo and they were full of water.

Does any one know how water can get in this cavity and could this be getting to the battery compartment.

1 I have checked the from windscreen drains and they pass water through to outside
2 I have replaced rear light seals
3 I have removed rear bumper and sealed air inlets and metal seams
4 I have test 3rd light seems ok
5 I have checked cab air filters and they are dry

Regards Jeremy

 

[CrustyClam]

Biggest leak I had was via a sneaky seal hidden behind plastic trim, This caused quite a bit of water in the boot for me.

new seal was just over £4 at the time I bought it. Once in I surrounded with a good outdoor weather sealant.

 

[mioba]

A good idea that I have seen mentioned on her by others is to apply talc powder to the inside of the car in the suspect areas and let it rain You can then follow the streaks in the powder and hopefully find the leak point.

Years ago I realised my boot well (W251) was full of a good inch of water. I couldvt find an entry point and put it down to driving in very heavy down pour - during the big floods in Germany a few years ago

Upon inspection in the wheel well is a rubber vent. They are very clever by design a - as you drive they suck stuff out - ie water from perhaps having changed a tyre on a wet road. On close inspection mine had a bit of a leaf in it and a poke. Been fine ever since.

 

[Mark A]

I moved the SAM on my ML420, there is enough give in the wiring to have it sit vertically rather than horizontal.

 

[pikeface999]

cheers guys will look into your suggestions, still would like to understand if water can get from back of truck (my photo)to battery box sam