KevinJ

Hi all, I have a weird thing of late. My battery is getting drained and will not hold a charge in this cold weather in England for more than a week, I have even not used the alarm and locked the car with the pull out key.

The battery went out completely this weekend and so I called out the AA breakdown services. The guy came and checked the battery output and it was around 3.x volts, he then boosted it and saw that the battery was being drained at a rate of 1.02 (volts I think, sorry not sure on this but he said a normal drain is around 0.2 ?). He put in a new battery which they carry around with them and the same story.

He said the battery is ok but something is draining constantly, not the alarm as it is never on now and during our tests, not even a light.

He then did some checks on the fuse boxes, particularly the one under the rear right passenger seat which is where we found something horrible. The fuse box and many other components where covered in around 2 inches of clear water. Everything seemed to continue to work and he sucked the water out with an anti-freeze tester (a kind of squeezy test tube thing).

Around 4 years ago I had the problem where the drain under the bonnet got blocked and overflowed into the car via the heating/cooling vents and flooded the front passenger side (UK) and made the SRS warning light come on. A valet and a trip to the Service Staton sorted the message at the time. Could this water in the rear fuse box area be related from this time ago?

NOW my current Title problem in addition to where is this water coming from, is that the registration plate lights are misbehaving. The right one is constantly on, if lights are on, if lights are off and if the car is SWITCHED OFF!!!! This is obviously a constant problem and will drain on the cars battery but this did not exist before as I would have seen the light on at night time.

The left light does not come on, but if I remove the bulb from the right, the left comes on slightly and flickers.

I looked at the fuse diagram and it says the fuse for these registration lights is an Electric Fuse?? What and where is this and can it be the cause.

If the cars lights are switched on, the registration plate lights behave normally and are not a problem. But if the lights are off and/or the car is switched off, then the above occurs and is a problem.

Any ideas would be greatly received but I feel that the water has damaged an electric fuse under the rear seat?

Thanks in advance

bamberger_1

All the lights in the W220 are electronically secured. I don't exactly know where the device is located. But I have found some information concerning the ingressing of water. Seems to be a known issue. It seems there is a tapped screw hole in the driver side (British) fendor, which is closed by a tape only. This tape may detach over time and water is sucked into the door sill and then wanders to the rear. There is another hole, where cables run through and the grommet may be not properly attached, and the water seeps into the area under the rear seat. Just check the pictures.

KevinJ

Many thanks for reply bamberger

Can you confirm the location of the 1st picture, you say front right fender, is this the front o/s wheel arch on a UK car, as I don't recognise the picture too well.

Thanks again for your help, I am having the car looked at today for the electrical faults and I shall check these entry holes out asap, upon it's return to me unless of course they find these too.

Cheers

bamberger_1

,

KevinJ

Many thanks again.

I shall check this out at the weekend hopefully. I am also going to have the car put on the STAR diagnostic system, to hopefully tell us what is wrong with the lights issue.

Does anyone know which component (probably one under the rear seat), that controls the lights, including the registration lights?

I would like to remove this component and dry it out myself (feeling pretty confident)...

I have come to the conclusion that I need to get rid of my S Class now and go for something that I can afford to run, as my finances have changed since my daughter came along you see. Maybe my fiance's A Class?

But I feel I cannot trade my car in it's current state (i.e. one regstration light permanently on)... Any comments on this would be welcome, i.e. who would correct this before trading etc and who would not ..?

Thanks....

KevinJ

I have managed to removed the electrical components from the rear passenger seat area and dry them out.

I have cleaned all connectors and plugs with electrical cleaner, then replaced it all a week later.

I am pleased to say this worked a treat and all is fine now.

I still need to check the possible water entry holes and described earlier in this post, but so happy everything is back to normal.

Many thanks to all that assisted me here..

Got to get rid now though....

KevinJ

I am finally getting round to taking my car apart abit more to check for possible blocked holes, open holes etc which is causing the water ingress.

On the 2nd post of this thread, bamberger_1 posts 2 pictures. The 2nd picture I believe would be under the rear seats at the back, but wondered how I remove the backs of the rear seats.

I can easily remove the seat cushions themselves to get to the electronics which I have previously removed and dried out, but wondered how to remove the backs? Is this tricky or nessesary?

I need to marry up the 2nd picture to my car as I cannot figure it out at present. I am going to check all drain holes around the car and do small tests by pouring water over every possible area, one at a time and then check the rear seat electronics area.

Hopefully.....

samvel1981

their is fuse box (SAM) under that box there 2 drain plugs take the box out and check them may be they aren't there
the fuse box not that expansive for Mercedes parts I'm but mine for $125
at junk yard
the dialer sell that for $247 if I'm not wrong
the web site http://mercedesbenzgenuineparts.com/
check may be they wood ship to you i don't know sorry
and good luck to you fixing

KevinJ

Well I took a good look at the car this past weekend (Saturday's weather was dry for the morning!!).

I looked at what would be obvious causes for my water ingress into the rear seat area. I first looked under the bonnet (raised into service level height) to follow what happens to the water from the windsheild and bonnet etc when going through the grated area at the top of the bonnet.

It all collects into a large plastic dish which spans across the grated area to catch the water. If the car is flat or leaning towards the passenger side (UK) then all water will flow into the large reservoir tank with the problematic rubber drain plug thing at the bottom. (Mine was blocked 3 years ago and flooded the front of the car which seems to be common). This was clear and has been since.

I then tested what would happen if the car is parked so that it leans the other way (drivers side - UK) and found that the large reservoir tank becomes redundant and the water goes towards the other side of the large plastic dish area. The design has a small rubber outlet to stop overfilling of this large plastic dish item, but with the car parked leaning towards the drivers side, this too becomes redundant.

I removed this large plastic dish item to get a better look.

Then it hit me, the drivers corner within the engine (UK driver side) is where all of this water will be directed and so upon looking closely with a torch, this area was choc full of leaves and mush (broken down leaves/dirt & sludge), and created a kind of small reservoir itself.

"This can't be good and must be the problem" I thought to myself. I vacuumed as much as I could and scraped out the crap which a long screwdriver, paper towelling, fingers etc and then vacuumed again. This area has the windscreen washer pipes running from the engine area to the washers themselves and so had to pull the pipes away slightly to get to this area.

I then retested and no more water collecting. It now runs straight out of the front drivers (UK) wheel arch area through a drain hole and some also came out of the rear drivers (UK) wheel arch area through a drain hole, so hopefully this is it.

I checked the rear seat area with all electronics and no water came through

I checked again yesterday and all good bar a small amount of water trickle which seems to be coming from the wiring tunnel from the front of the car to the rear (i.e. where the water is getting into the rear seat area from) which I am hoping is merely the water left from within this tunnel from before my fix and not fresh.

I am now planning to use a mains powered dehumidifier inside the car to draw off the remaining water/moisture as the weather sucks in the UK about now until April. Can someone recommend do I close all windows when this dehumidifer is on, what percentage setting should I use and I guess I will know when it has done it's job as no more water will collect?

Sorry if the above goes on a bit, but I am thrilled that I (hopefully) have found the culprit for my very frustrating water ingress problem.

p.s. It rained all day yesterday and was parked in the position that caused the water problem beforehand and all was good (apart from the small trickle which hopefully is what I said above).

Thanks

Jerry-

I looked to find this "nest of leaves" described above and found one, behind the fuse box on the right hand side. It is a UK car so it might be the other way around for you.

I uploaded 3 pictures with increasing zoom, so you know where to look.

Can anyone who has cleared off these leaves elsewhere tell me where to look? I have a V12 engine and there is no obvious place I can see from just glancing in. The water collection cowl on the left is already cleaned. I removed dirt from the area under that grid. I am looking for more places.

JackPara

Hi Jerry, how did this story end? I have the same problem. I'm looking for a solution.