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1997 E420
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Discussion Starter #1 (Edited)
I have a 1997 E420 which has the flip key IR remote and those exposed red and green light IR sensors. I had given up on ever getting this system to work, but then I discovered that you could actually see IR light with any digital camera. With that discovery I was literally able to see that the IR receivers on my rear view mirror and trunk still worked, but not the one on my driver side door. With the trick I was also able to see that my flip key only worked intermittently, and I discovered that it was the button itself that was faulty even though it pressed properly and solder joints were intact. I then noticed that the top part of the button holding the silicone piece could be removed exposing the button dome and three contacts, as you can see from the picture below. I cleaned the three contacts and button dome, and now the flip key works 100% of the time! You can click it as rapidly or keep it pressed, but the IR light is now always visible through the camera at every button press. I hope this helps someone in the future!

Anyway, does anyone know if someone sells replacement IR receiver covers for the driver side door and trunk? I guess that one could fashion their own waterproof solution with a piece IR film or plexiglass and some hot glue...

What about the driver side door receiver itself, is it possible to repair? From some old forum posts I've read, it seems that new replacements are very expensive, and that you can't get used replacements because these receivers are somehow bound to the individual car they came from... How true is this?

Edit: Actually, that might only be true for door handles that have both the key tumbler and IR receiver. I remember replacing the damaged door on my 1999 E320 and that receiver still worked. I put the old handle from the damaged door on my new one to retain the original tumbler and functionality.



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Ricky,
These links might assist you further:



 
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1998 MB E300TD, 1997 MB E36 AMG, 2001 MB E55 AMG
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Anyway, does anyone know if someone sells replacement IR receiver covers for the driver side door and trunk? I guess that one could fashion their own waterproof solution with a piece IR film or plexiglass and some hot glue...

What about the driver side door receiver itself, is it possible to repair? From some old forum posts I've read, it seems that new replacements are very expensive, and that you can't get used replacements because these receivers are somehow bound to the individual car they came from... How true is this?
No, because I would've been all over those aftermarket IR receiver. Unfortunately there are none, so you're stuck with the dealer option @ $250 a pop. But according to those reports it works perfect, and used ones are junk....because they break anyway.

You can try to repair it, unfortunately MB didn;t exactly release a semantic diagram of the IR receiver internals. They don't do that at all, never mind on a single part that was confined to 96 and 97 vehicles in orphan model year vehicles.

I've heard people been able to successfully retrofit used trunk receivers into the driver side IR, but then you're left fabricating the remains of the trunk receiver into the door receiver and then making it look OE is apparently hard.

My problem with the IR receiver in my car is that because it's defective, it sends out garbage on the wires (all three receivers go to the DAS module to my knowledge) and if one receiver induces garbage in the line, it pulls down the whole system and the IR won't work.

So far I have "repaired" mine by unplugging the door receiver and thus made the IR work 100% of the time. I always use the rear view mirror or the trunk.

They are not coded, they are dumb terminals and they only transmit the IR frequencies and data to the DAS module. If the signal is clean and the DAS module receives the full IR signal from start to finish and it corresponds to the info stored in internal database, then it sends signal to unlock the door.

But if the signal is garbage, even if the beginning of the IR frequency is clean but the rest of it is scrambled due to interference, then the DAS module ignores it.
 

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1997 E420
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Discussion Starter #4
@khomer2 @Deplore Thanks guys! I'll pull the trunk and door receivers and see what I'm working with tomorrow. I cringe hard thinking about all the times blasted these receivers with my pressure washer... I'm surprised the trunk one still lights up and works lol There are a couple of E420's and my local Pick Your Part right now, I'll pluck their receivers and maybe build a working one with some soldering if the don't already work. I've soldered far more complicated things in the past lol

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Discussion Starter #5
@khomer2 @Deplore I thought I'd also pull the passenger side tumbler because it was not working. Do you guys know what the broken piece is called or have a part number? I thought that I was being clever by pulling the tumbler from a spare 1999 door, but in typical Mercedes fashion it's been redesigned from my 1997...


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ricky,

See if this helps.
epc from a 97 e420

 
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I've bookmarked this, because this is the same exact setup as in our 97. Just build your own instead of buying new one.

I'm planning on repairing my lock cylinder this way as well, since this is also broken on my car.
 

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1997 E420
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Discussion Starter #8
ricky,

See if this helps.
epc from a 97 e420

It looks like they have the entire tumbler assembly as a single item. I'll just add the broken part to my list of things to get for when I go to the salvage yard. It's super easy to pull these door handle parts anyway.

The working trunk sensor was starting to corrode, but I brushed the excess corrosion off and the blasted it with that CRC QD Electronic Cleaner.

I did the same with the driver door sensor but it just show how much of it has been eaten away by the corrosion.

I had a spare sensor from a broken rear view mirror, but they had nothing in common lol


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Discussion Starter #9

I've bookmarked this, because this is the same exact setup as in our 97. Just build your own instead of buying new one.

I'm planning on repairing my lock cylinder this way as well, since this is also broken on my car.
Hahaha, I watched that video last night, and I was like fuck that... I'm going to the salvage this week anyway. Let me know what other year and models use the same tumbler, and I'll grab one for you too lol

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Yeah the sensor from the rear view mirror is a little bit more complicated, it also runs communication to the DAS for the red green lights, plus IR receiver on both sides of the mirror, plus a little fancy algorithm that allows the receiver to compensate for the glass, since IR signal is refracted through safety glass.

Try disassembling the door receiver and trunk receiver, then unsolder the IR from trunk, solder the PCB from trunk to the IR receiver on the door -- use wires so you can shove the PCB somewhere in the door panel so it doesn't stick straight out and interfere with the glass.

That was my other thought, because well... $250 buys me a lot of beers. And if I don't have my beers, I'm sad.
 

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1997 E420
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Discussion Starter #11
Yeah, the connector and PCB are the same except for the indicator lights/IR receiver module. They say that functioning trunk sensors are most common, so I'll most likely do like you said. I found a strip of black plexiglass used to dim the LEDs of an old modem that will work nicely to reseal weathered part of the sensor cases. I want to do it right. I want my cars looking brand new lol


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Hah, nice cars.

The purist in me is balking at the V12 badge under the S600 and the W211 rims on the E420.....but I have no room to talk, since my cars aren't perfect either.

Are both E420?
 
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