Strange issue .. need advice




It’s just inherent in the design when you place all the sensitive electronics in the false floor underneath the beltline that any water leak through the cabin, air filter box or tail light seals or third row sunroof will all accumulate in that space.
I would have the car read out on a MB star system, or if you have an Aurel 808 with a Mercedes specific module, and interrogate/short test the whole car and see which modules aren’t answering. Those will be your water damaged ones and those will be the ones causing the interruptions.
if you’re unable to DIY, this expect to pay out the nose, probably more than the car is worth to get everything fixed.




thanks for the response. All those areas are dry of water and I am totally a DIY as o have the Mercedes star computer. At first I wasn’t even getting Audio but after cleaning the board I regained audio. That said I already had the rear same read and no errors came up. Replacing the sam isn’t a big deal as I can get used one with warranty on eBay and reprogram it to my car. Just trying to figure out if the light switch is related to the front sam or rear sam.
It’s just inherent in the design when you place all the sensitive electronics in the false floor underneath the beltline that any water leak through the cabin, air filter box or tail light seals or third row sunroof will all accumulate in that space.
I would have the car read out on a MB star system, or if you have an Aurel 808 with a Mercedes specific module, and interrogate/short test the whole car and see which modules aren’t answering. Those will be your water damaged ones and those will be the ones causing the interruptions.
if you’re unable to DIY, this expect to pay out the nose, probably more than the car is worth to get everything fixed.
so rule that out first.
I know that the fuel pumps and fuel sensors are on the rear SAM so I think the division line would be right behind the B pillar, but Mercedes may not have followed my logic.
Welcome to the 164 forum, you sound like our kind of guy, fully DIY and equipped with star.




so rule that out first.
I know that the fuel pumps and fuel sensors are on the rear SAM so I think the division line would be right behind the B pillar, but Mercedes may not have followed my logic.
Welcome to the 164 forum, you sound like our kind of guy, fully DIY and equipped with star.
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Glad to see you joined us “Gluttens” .
I just bought another 164 and after a bunch of maintenance got a few trips under my belt and will be starting a front wheel bearing project in the AM… was surprised I have a failure under 80k miles?? Well kinda of surprised 😂..
Ok welcome to the party also have a couple of Star Systems and will gladly learn what I can from you on the Star systems.
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I owned this 08 since 2012, have replaced the amp before and actually to prevent water building up I took out the drain plugs that are near the amp. I have also checked all those areas prone to getting water and they are completely dry. As preventative maintenance all the drain plugs have been removed so that no water can build up. As far is my issue it’s clear to me based on the fuse diagram that the light switch and instrument cluster is fuse 55 on the rear fuse panel which is obviously connected to the rear same. My issue is probably the rear sam board got too much water somewhere on it and is causing my issue. As I said I have owned enough Mercedes to know they were built like crap lol . I will buy a new rear sam and program it. I don’t plan on keeping this truck past November of this year. Nothing is wrong with except this issue and is actually at 98k miles. All the suspension parts have been replaced and the transmission service was done at 50k miles and I will do it again in the near future.
Glad to see you joined us “Gluttens” .
I just bought another 164 and after a bunch of maintenance got a few trips under my belt and will be starting a front wheel bearing project in the AM… was surprised I have a failure under 80k miles?? Well kinda of surprised 😂..
Ok welcome to the party also have a couple of Star Systems and will gladly learn what I can from you on the Star systems.








very sticky and gooey friction tape that wraps those wires are a telltale sign of moisture in there.




if those are the boxes, I’m thinking of they’re fairly well elevated over the gas tank caps to be out of the way of sloshing water. Could be Coke or latte damage though.




I am still leaning to something in the fiber loop only gets powered with the lights which will go back to a nasty fuse box ?
























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