1995 W124 E420...the convenience feature on my vehicle is not operating consistently...windows, locks, and sunroof operation are all normal/no problems...however, sometimes, when I press the window down next to the selector for the front window to roll all the way down by itself...it does not come down automatically all by itself...also, when I hold the key down so the sunroof/windows close, it sometimes does not work...is there a module that controls this operation/function? is there a fuse I can reset? It works sometimes, then stops working other times...I've used the system pretty often on my vehicle and it has only been acting up lately... Thank you for any insight into the problem...

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1995 black pearl/black Mercedes-Benz E420 :

The convenience features control module (n57) is located under the rear seat (drivers side)

It should have a p/n: 202 820 09 26

There is also a convenience relay module in the fuse box (k24).

Are both of the one touch features broken or just the drivers side? and is the problem intermittent or is it contant? I mean are the CF features broken now when the used to work? or do they still work sometimes and not others.

Good luck!

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Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE

The convenience features have worked perfectly before, just that the last two weeks, they are working intermittently...they are not broken completely...now they sometimes work, sometimes do not work...they problem pertains to both the driver's side and the passenger's side...

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1995 black pearl/black Mercedes-Benz E420 :

Hmm...I don't know what to tell you. Its likely the comfort control unit or the relay. I think that a dealership could pull the codes, but the fix is probably replace one or the other. I guess the dealership could swap out the convenience control and relay to see if either are bad.

The relay is p/n: 0015427819 ($43 on fastlane)
and the control unit is p/n: 202 820 09 26 (not listed on fastlane)

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Daily Driver: 02 E430 4MATIC
In the family: '03 E500 // '04 ML500 // 64 220SE

Is there any way to troubleshoot the problem myself?

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1995 black pearl/black Mercedes-Benz E420 :

What is the purpose of the convenience feature module? Does it only control the convenience features, i.e. window auto down and close/open all windows/sunroof when key is held in the lock/unlock positions? Is that it? Kind of pricey at around $450CAD for the unit...do you guys just leave it broken and live without having those features or should it be fixed? Does it actually do more, and these failures that I have been seeing are simply just the start of more problems so the unit should be replaced??? The shop said the original module had defective solder points and the module breaking down is a pretty common problem...which kind of confuses me...what exactly is a defective solder point? I mean, if the solder was defective, I would think that it would corrode/rust if it was located in a more "harsh" environment...but tucked behind the back seat doesn't seem all that bad...

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1995 black pearl/black Mercedes-Benz E420 :

I have little problem in convenience feature module my 2nd cable is always disconnected when i try contacting the 2nd cable to it's place the sunroof is opened by itself and keep continues until i disconnected what's is this problem and how can i solve it

Check on eBay for a used module for advertise for one here on the parts board. I got one from David Hendy on this board for about $40 and it solved my problems.

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1974 Porsche 914 | 1980 Porsche 911SC
2002 Porsche 911 | 2002 Mitsubishi Montero | 2011 VW Golf