This forum gave good information during my research regarding replacing the headunit on my 2002 E320. Big thanks to Steve. Here's a write up of the VERY EASY process for replacing the bad Becker headunit and taking full advantage of the good stock Bose amp and speakers.

Here is how to replace the Becker headunit in a 2002 W210 (and maybe many other models from the similar year), keeping the Bose amp and speakers. Though everyone says Bose is crap, I support the few who blame it on Becker. Comparing the same CD through the Becker and my headunit, the aftermarket unit had better bass and MUCH better treble. "No highs, no lows, must be Bose" is untrue. It's well worth this very easy upgrade.

Get the radio removal tools to pull out your Becker deck. Part # W 000 589 88 63 00 ?

Get a Metra #70-1784 "Volkswagon" harness from Crutchfield. This attaches to the A (power/control) and B (amp audio input) connectors on the wiring harness. The wiring harness C connector (teleaid?/CANBUS?) and fiber optic (CD changer) are not needed.

You may need an antenna adapter if you're connecting radio, but I'm not at that step yet.

If your headunit has RCA female jacks for preamp line-out, get four high-quality RCA male plugs to solder onto the Metra harness. Get high quality solder with high silver content and heat shrink tubing to seal all solder joints.

The definitive power/control list for 2000-2002 W210 E320, by mbworld's famed "Steve":
https://mbworld.org/forums/showthrea...light=headunit
1 (was green/black VSS speed sense wire before 2000, now tucked under passenger door sill "cable gutter" after 2000 update. VSS now over CANBUS.)
2 gray wire--diagnostic connector pin 33
3 black/yellow wire--mute the radio as soon as you connect it to ground (telephone mute)
4 red/white--constant 12V just like your diagram
5 blue/white--remote turn on lead just like your diagram
6 empty
7 empty
8 brown--ground wire just like your diagram
CANBUS (brown and brown/red wire in C connector)

You'll notice there's no switched 12V, illumination, or dimmer sense wires. These may be controlled over CANBUS, but I don't know. You can wire the new headunit's switched 12V to its constant 12V, and wire those two to the Benz constant 12V. This leaves the headunit on ALWAYS, even when the key is out, so do this only during testing. I wonder if that leaves the amp on also, via the amp sense line. Run a line off the cigarette lighter positive terminal or something switched to get the true switched signal (which I haven't done, so I can't advise). Illumination and dimmer may be able to run off the headlights somehow, unless they are also on CANBUS.

The speaker wiring matches the Metra harness exactly. Pin numbers can be seen on the connector where the female plugs are. Here it is for reference:
1 Left rear + = Purple/Black
2 Left rear - = Yellow/Black
3 Right front + = Yellow/Black
4 Right front - Yellow/Brown
5 Left front + = Green
6 Left front - = Yellow
7 Right rear + = Brown/Red
8 Right rear - = Brown
This probably matches the 99 E class and 01 E430 which have similar colors that I saw while researching this. https://mbworld.org/forums/showthrea...light=headunit

The 4 Volt RCA line-level preamp outputs on my headunit fed into the Bose amp with no line-to-speaker-level converters. The Bose amp was slightly quiet, requiring the headunit at half full volume to be heard well while driving. Maybe I can increase the gain on the amp. There was no static (suggesting low input voltages) or overdriving (suggesting high input voltages) like other posts have suggested. One SLK installer said the amp can take speaker level or line level input, but I have not tested that.

This install should only take a few hours (mostly for the soldering) and essentially only costs the new headunit. Don't let any professional installers tell you it's not possible because they didn't do all the research and testing that I did. The Bose amp and speakers really seem to resonate well in the car (open the door and put your ear next to one and it sounds weak), so I suggest not replacing them. Maybe a subwoofer is needed, but I'll worry about that much later. I hope this helps someone.

 

Sorry, I posted the rear speaker wires incorrectly. Here is the updated layout for the speaker wires, matching the Metra harness exactly. Sorry for the confusion.

1 Right rear + = Purple/Black
2 Right rear - = Yellow/Black
3 Right front + = Yellow/Black
4 Right front - Yellow/Brown
5 Left front + = Green
6 Left front - = Yellow
7 Left rear + = Brown/Red
8 Left rear - = Brown

 

Copy and paste from my Benzworld.org followup post, finally. Here are the missing bits:

To use the car's antenna with an aftermarket deck, you need:
Metra Antennaworks antenna adapter #40-VW12 for VW/Audi


True switched 12V and headlight/dimmer sense are available; the CAN BUS connector can be completely abandon in the dash:
Switched 12V comes from the yellow/black wire on the cigarette lighter. Dimmer sense comes from either of the purple/red wires on the cigarette lighter. The brown on the cigarette light can serve as an extra ground if necessary. Use tap-ins (blue, 16-18 gauge, water resistant) to run a line to the wiring harness.

Removing the cigarette lighter tray to get to that wiring can be found at this Braingears or the mirror:
http://mb.braingears.com/W210/w210/d...nter_step2.htm
http://w210.pietrzyk.net/disassembly_interior.htm


You may need to convert your 2 Volt unbalanced line level outputs to 4 Volt balanced signal which the Bose amp supposedly expects. This can supposedly be achieved with:
Peripheral Super VEN 4 - http://www.cardomain.com/item/PERSVEN4
I purchased one but have not yet tried it. Without it, my headunits are "too quiet", requiring them to be turned up higher than I'd like in order to get a decent volume. See posts by BenzWorld's DickB for insanely detailed information:
http://www.benzworld.org/forums/r170...-question.html
http://www.benzworld.org/forums/r170...ewb-stock.html
http://www.benzworld.org/forums/r170...questions.html


My final install pics can be seen at this post:
http://www.benzworld.org/forums/audi...benz-pics.html

I hope these posts help someone.

 

Nice work on that stereo, turned out fantastic....maybe you want to help me with an install once I get my HID conversion finished.

 

FireFox31

Thanks a million for the concise explantion and the dissasmbly link.
It's greatly appreciated.
One question. If the RAC jacks out of the head unit are 4v is the output convertor still required?

Thanks

 

99 wagon:
The SVEN4 is not required, but it may help. I really don't know much about the 4V Bose requirement other than what one poster said numerous times. Of my two installed headunits, one puts out 2V (Alpine) and one supposedly puts out 4V (empeg/RioCar). They both appear about 25% quieter (at highway speed) than an identical setup in my Volvo using a low-end Alpine amp. Granted, the Volvo's door speakers are really high, while the Benz speakers serenade my shins.

Once I'm done frying iPods and stock headunits in my sister's cars (oi, long story), I'll try that SVEN4 that's sitting on my desk. I have a hunch it won't help line-level at all; instead designed to reduce speaker-level (who in the world would do that?). We'll see....

I swear the highway speed quietness is from some speed sense in the amp.... I have no way to tell though. The install sounds good when parked, but just weak at speed.

 

This has been sooo extremely helpful, thank you. Did you ever do anything about a sub upgrade to go with this?

 

I'm going to bump this, since a lot of people have been asking about HU replacement recently. I've done this twice on a MB, and used this guide both times.

 

The links for the cigarette lighter replacement is missing. Can you provide new links or tips to replace cigarette lighter. The one in my car is bad connection, does not have stable socket. Of course I do not wan as lighter mainly as power for ther items to plug in reliably.