[QUOTE=TriX5;727460Question, anyone know what the white mystery plug is for?[/QUOTE]

It'll be X322 or X400. Refer to the wiring diagram, it should be easy to locate.

Been trying to find a diagram online but no luck, where can I find one?

This afternoon decided to check the color coding on my new harness and all was well. I received the BM53 radio 2 days ago and I am now only short the CD changer which I am sure will be coming in soon.

In doing the color check I discovered 8 of the 10 speakers run through a single plug of the three on the amp. This plug contains no other connections. The remaining 2 speakers are connected to the main plug on the amp. I realized this would allow me to keep 8 speakes in the car connected while connecting the new harness to everything else.

So I connected the new OBM, the nav computer, and the new radio to the new harness. Then plugged in the new harness to the subwoofer and the amp (except for the speaker plug). Finally plugged the harness into the main plug to the car (first of the three connectors attached to the amp frame). This left two speaker connections in the new harness needing load which I hooked to a pair of old Pioneer speakers. Then hooked up the ground, turned on the power and voila!!

(one minor thing, there was a plug in one of the blank holes of the connector to the car main harness which I had to remove and insert in another blanks space, nothing crucial there).

As I don't yet have the GPS antenna couldn't navigate but otherwise the Nav computer worked fine. The tape deck faithfully played one of my trusty old cassettes. Radio was fine and B/T seemed operational. I am still in the dark what the red nav connector does but so far so good.

Conclusion: As far as I can see this is most definitively a plug and play affair and I am impressed that new loom is exactly correct for my '06. I would say that the only quirk indeed is having to reinstall the speaker wires all the way into the doors. Have to make a decision on that very soon now. I am stumped why dealers would refuse to do this retrofit, it is really easy, especially if you have all the clips and other hardware handy!!

So far I am thinking I will cut the existing speaker wires off the old harness and connect them to the speaker connectors on the new harness leaving the excess coiled under the carpet. However, I would have to find some connectors or at least pins that fit the speaker connectors, anyone have a suggestion where to get them?

Funny how I could plug everything in and run it quite without installing anything but it was worth the effort to know that all pieces were operational and that the car made no bones about running them. See below a couple of pictures of the affair, not very usefull as there is too much of a spagetti junction but there it is.

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Here's some retrofit instructions. For E38 but the loom is nearly identical

http://members.shaw.ca/dragnet/image...v_retrofit.pdf

I suggest if you have existing DSP then leave speaker wiring as is on DSP plug and just transfer the wires you need

All info is also in the WDS:
WDS BMW Wiring Diagram System - Model Selection

Project is a bit slow because of a medical hick-up on the domestic front. Finally making progress again this weekend. Still haven't figured out what the red Nav connector does but it sure does something. I connected things up today and the Nav does not navigate, I am stuck in Atlanta.... However, the Nav works fine on my 03 so something is not right yet.

Anyway, the new harness is in from the radio to the front with the OBM connectors sticking out just ahead of the shifter. Plugged everything in and music all works fine, the TCU works, can connect with BBerry and make calls, etc. So, the wires to the red nav plug is probably what is missing but as long as I don't know what that wire does I am a bit stuck there, BMW parts guys have no idea unfortunately.

I decided for the moment not to demolish the doors and therefore took the speaker wires out of the old harness. This means that temporarily I have a loom with just the old speaker wires running along with the new harness. Couple of pictures below to show the level of the madness....

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Here is a picture of the stripped old loom and of the new harness with the speakers wires added in separate bundle. The speaker connector in the new harness will be replaced by this one for the moment.

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The red connector contains the speed pulses, and reverse signal, and 12V ACC power.
The speed signals are crucial, if you have a Mk3 then the nav will not navigate smoothly without the speed signals.

Speed signals come from the ABS module, but you can also pick them up from other locations depending on what equipment is fitted.

You don't work for the bomb squad do you? Because it just occurred to me that this would probably make a pretty good training exercise.

I drive a desk for a living but that is a whole another story.

Last night I did the needfull! Straddled the shifter (the seats are still out) and took the hacksaw to it. This project is not for you if you are sensitive to your neighbours' stares...... They are still wondering when we'll buy a respectable car....like a Lexus Hybrid or something, not a growling V8 with oversized rubber and clear boy racer aspirations.....

Anyway, I was weary of using a recip and bought a handle that takes recip blades. The plastic is not that hard and a sharp blade makes quick work, even by hand. It avoids accidentally cutting the bottom of the opening, I know I would have had problems with that using a recip.

The instructions are clear and correct but the only thing I did not do are the cuts for the top bracket since it is not available from BMW anymore. I simply used a 5/8" wide file to deepen and widen the notches already in place so that the 2 brackets fall into them. I attached the bottom but not yet the tops of the brackets as you can see in the pictures. I compared the upper position to the '03 and, once correct, the notches for the brackets are about 12mm deep.

The cuts to the tabs on the side are not that critical to the whole thing so I scored them with a Stanley and snapped them with a sheet metal bending plier (the 4" variety for HVAC duct work.....don't ask...). The only problem I still had after all this was that the sides of the old opening still stuck out above the brackets and the OBM falls flush with the brackets. So it was wobbling a bit and not fitting well top and bottom. To correct this I scored the plastic (using the top of the bracket as a guide) and snapped the pieces off, then smoothed the surfaces with a Stanley knife.

Since there was no wild action with an electrical recip a hand towel at the bottom of the radio opening sufficed to catch the debris, the towel catches the shavings nicely, kind of clings to it. Last picture is the OBM in place!

I just have to figure out now how to attach the tops of the brackets but for the moment I will focus on finalizing the connections to the speakers and getting the interior back together so the car is not such lump sitting around. Then the GPS antenna has to go in place and after that I will finalize the OBM installation.

Hope this is usefull to you all, I am enjoying it even if it is taking some time. Wife is not driving yet and I am using the '03 for the moment so all is well.

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