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Hello- two days ago, after torrential rain, my S600 started displaying "Display Defective" with lamp symbol and "Check Lamp". In addition- the rear brake light above passanger seats stays on- no way to turn it off. I tried disconnecting battery and reconnecting but it did not help. Finally, the fuel gauge does not work.
The car has 58k and has had tons of work done over the years. The battery is 1 year old.
I now live in rural upstate NY and it is hard to find a good mechanic here much less one that knows German cars.
What on earth is happening this time? I would appreciate your advice.
And- is there a market for these cars? From what I saw so far it is not worth much
Under the hood, on the right side (always from the seated driver's viewpoint) at the rear of the engine compartment is a large black plastic grid. This covers the HVAC air intake plenum. Inside, at the bottom of the cone-shaped plenum, is a small drain hole. It is common for that drain hole to become plugged with leaves and debris, which causes rain and wash water to fill the plenum. It then overflows into the inside of the car, going directly underneath the carpet padding and insulation. There will be no visible water inside the car. This water runs toward the rear of the car in the recessed channels stamped into the floor pan of the car. Along the way, it wets, and corrodes, the main power cable connections under the aluminum plate hidden under the carpet and padding. The water eventually makes its way to the rear SAM (Signal Acquisition Module), the fuse box, relay box and computer that operates much of the rear of the car, including the brake lights. The water causes corrosion, poor connections, and short circuits.
Correction consists of:
Opening the drain and keeping it open and clear.
Removing the seat, carpet, padding and insulation on the right side of the car.
Drying everything out completely, including the rear SAM.
Correcting all corrosion and poor contacts.
Takes a lot of work and time. The longer you wait, the worse the situation becomes, and the more difficult the correction becomes.
Under the hood, on the right side (always from the seated driver's viewpoint) at the rear of the engine compartment is a large black plastic grid. This covers the HVAC air intake plenum. Inside, at the bottom of the cone-shaped plenum, is a small drain hole. It is common for that drain hole to become plugged with leaves and debris, which causes rain and wash water to fill the plenum. It then overflows into the inside of the car, going directly underneath the carpet padding and insulation. There will be no visible water inside the car. This water runs toward the rear of the car in the recessed channels stamped into the floor pan of the car. Along the way, it wets, and corrodes, the main power cable connections under the aluminum plate hidden under the carpet and padding. The water eventually makes its way to the rear SAM (Signal Acquisition Module), the fuse box, relay box and computer that operates much of the rear of the car, including the brake lights. The water causes corrosion, poor connections, and short circuits.
Correction consists of:
Opening the drain and keeping it open and clear.
Removing the seat, carpet, padding and insulation on the right side of the car.
Drying everything out completely, including the rear SAM.
Correcting all corrosion and poor contacts.
Takes a lot of work and time. The longer you wait, the worse the situation becomes, and the more difficult the correction becomes.
Sorry about that...
Thank you very much Wally for your kind reply. Will take it to a mechanic on Monday. Have a great weekend!
No! Do not start or move the car , the water will continue to short out electronics !
Check if there is pooled water in the black plastic reservoir under passenger side windshield - use a flashlight if needed . If there is water in there you must clear the drain first before moving the car .
But! Don’t remove the water without taking pics and if you have comprehensive coverage on your auto insurance file a claim as this is covered under water damage. You need to document the wAter was there .
Then use a long screwdriver or chopstick to clear the drain at the bottom of the reservoir . The water should pour freely under the car .
then pull up the front passenger carpeting starting under the dash and soak up all the water on the floor under the foam carpet pad . No tools are needed the carpeting it just pulls up all the way to the base of the front seat
lastly pull off the rear seat bottom (there are two clips takes 5 minutes ) and dry out the rear SAM module under the rear seat . Use a hair dryer or similar . Powering up that wet module can cause you thousands in damage . It might still be saveable if dried out
Only then should you power up the car and try driving it
Dear Tusabes- thank you so very much! Unfortunately I have driven the car for about 30 miles in the last couple of days. I will take your reply to a mechanic and hopefully he will be able to follow up on your recommendations. You have been most kind and thank you again!
Joanna
Yes I understand you have already driven it , but what you don’t seem to grasp is that it’s still full
Of water at the rear Sam under the rear seat . and by not removing the water under the carpet and under the rear seat you are risking turning a car that runs into a brick that doesn’t run
its like driving a car with no coolant . You can drive a little bit to the service station with no lasting damage . But Keep driving it and you’ll ruin the car .
If you don’t remove the water before driving again it is gojng to continue to slosh under the carpeting front to back as you drive and ruin your entire car. There’ a groove in the floor pan that is totally full of water right now
But it’s your car and your decision how much further damage you want to cause
just know this is a $100 problem if taken care of early versus a $8000 problem if you keep driving it
The front is drying and now trying to figure out how to remove the back seat. The pins you mentioned are not obvious to me. Is it relevant that the car has "active ventilated rear seats"?
We had some pretty heavy rain last night, and I checked the HVAC plenum this afternoon - the drain was plugged! There were only about two or three inches of water, and it drained quickly when I cleared the drain. Hopefully, I didn't get any water under the carpet...
It is such an obscure detail and yet so good to know for which I am grateful to you. Waiting for my friend to arrive as we speak to lift the rear seat. Hoping for no damage aside from moisture. Hairdryer and towels ready. Sourced a SAM unit for under $100 just in case. Praying
Have a wonderful day!!!
There are many different part numbers for rear SAM and if you need one you need to buy the same part number as the one in your car - it will be printed on yours once you get the seat off .
Buying any random rear sam that says it fits may indeed fit but won’t work properly
keep in mind at this point there are still gallons of water trapped in the rear seat area under the carpet foam and in order to fully dry it , the passenger front seat will need to be removed so the carpet can be fully pulled up front to rear . It’s not too difficult for a mechanic but it must be done . Once you dry out your sam you can stick a rag or block of foam under it to keep further water from hitting it so you can safely drive it
then take it to your mechanic (or a stereo shop, auto detailer, upholstery shop or others that regularly remove seats ) for complete seat and carpet removal and drying
A few things that will help if you do have water damage - Google will tell you about them... Corrosion Block DeoxIt 5 Stabilant
Thank you very, very much!
Regrettably still have the same problem after all was dried. The battery was recharged today and after starting the car the same messages flashed: ABS, brakes, etc. The fuel gauge still not working and the brake light above registration plate is on.
Would replacing the rear SAM unit solve the problem?
Is it worth to repair it?
If not, what one does do with a car like that? Not much of a trade in value....
08-02-2019 | 04:38 PM
