I used these forums to figure out most of the wiring needed for installing an Alpine CDA-9833 in my 2000 E320 today. I wanted to fill in a couple of missing pieces I had to figure out on my own. Note: I also have the Bose system.
USE THIS INFORMATION AT YOUR OWN RISK!! I AM NOT A PROFESSIONAL AUDIO INSTALLER!!
I ordered a new Alpine from Crutchfield, and told them it was an Audi/VW the included these part #s with the Alpine:
120701758 VW/Audi Wiring Harness
120869001 OEM Tool pair for removing stock radio
097DIN2 Euro/Ford Antenna adapter
The Wiring Harness supplied fit my existing wiring harness, but not all the wires were in the right place.
There are two harnesses plugged into the back of the stock radio, the top one is 2x5 and was not used. The bottom connector looked like this from the back:
Code:
-------------------------------------
|Blk/Pur | Ylk/Blk|Green |Brwn/Red|
| | | | |
|Left R+ |Left F+ |Rght F+ |Rght R+ |
-------------------------------------
|Blk/Ylw |Ylw/Brwn|Ylw |Brwn |
| | | | |
|Left R- |Left F- |Rght F- |Rght R- |
-------------------------------------
|Empty |Ylw/Blk |Blu/Wht |Empty |
| |Unknown |Amp | |
| | |Turn on | |
-------------------------------------
|Grey |Red/Wht |Empty |Brwn |
|Unknown |Constant| | |
| |12V | |Ground |
-------------------------------------
I didn't actually check all the speakers to make sure they were in the correct places, so YMMV.
The only thing missing from the factory wiring harness was a switched 12V source and illumination. For the 12v switched I tied into the cigarette lighter, I didn't care about the illumination. The only wire I had to cut in the stock wiring was the 12v to the cigarette lighter.
Make sure you connect the remote turn on wire to the amplifier turn on, and not the antenna wire.
I tied the speaker outputs directly from the receiver to the speaker inputs to the Bose amp. The line levels may be a little too high, I'm going to try it for a few days, and if it is annoying, I will connect the RCA outs on the receiver to the wiring harness.