Well today I go to pull out the sony head unit in my 90' e34 expecting to find a wiring harness back there but I don't. I find that the wires from the hu have been directly spliced into the cars wiring. I'm not sure what color wires will go to what on my pioneer hu I want to install and also noticed that some wires from the car weren't attached to anything.
A description of the wires behind the hu:
There was a group of 4 wires - a yellow and brown orange twisted togeather and a blue and brown orange twisted togeather.
A yellow and white wire from a small white rectangular connector.
A blue black, yellow black, blue red and yellow red wire from a larger black rectangular connector. The blue red and yellow red are very short and go back into the same black connector they came out of.
Any help in explaining which wires go to what or what I need to do would be appreciated. Thanks

you should go to the store, get an adapter for your car first. then, hook up the adapter to the wires from your CAR (the adapter has labels on the wires to tell you what it's for). After that you should hook up the adapter to your new pioneer HU. I think that's the only way to do it :dunno

An adaptor will do me no good here because there is no car wiring with a harness to hook into. The only harness is the one that hooks into the hu and replacing that will just put me in the same spot I am now. I found a little info on bmw34e.com and it looks like my system might not have come with a harness to begin with, but I want to make sure before I go and start clipping wires and hooking stuff up. I do know what the wires comming out of my head unit are for. I just need to know which ones correspond to them in the bmw.

I don't trust following the wiring from the Sony hu in there already because it has done some strange things while installed like the volume not working sometimes or the radio signal not being there sometimes when I start the car. I'm thinking those 2 things might have been caused by some of the insulation being stripped of the antenna wire, exposing the braided shield. I wraped it in some electrical tape, to prevent it from touching anything.

Looks like you have a couple of options. You can go to a junk yard and cut off the harness from a wrecked car to splice it back into your car. Probably a good idea to solder and heatshrink the factory harness back in place. Then you need to buy an aftermarket wiring harness to attach to your Pioneer. After that, its plug and play. Cutting off the factory harness doesn't necessarily mean that the previous installer did a "hack" job. In fact, some installers don't like to use harnesses at all and prefer to just solder the headunit's wiring directly into the car's wiring. This will actually give you the best connection.

Ok, do you know if the harness wires would correspond to the ones in the car if it didn't have a harness in the first place? I'm not positive but I think some 90' radios did not use a harness. Could someone please confirm this for me. I understand that some like to hard wire the hu to the factory wiring but I'm calling it hack because there were exposed wires left behind that weren't insulated or capped.

...I'm calling it hack because there were exposed wires left behind that weren't insulated or capped.

Ok, I see what you mean by hack. Sorry, I can't help you with the e34. I can tell you that my 91 e30 had a harness. In the early 90's I think most, if not all, BMWs had regular sized headunits. That being said, I'd guess that the headunits were interchangeable from model to model in that era. So chances are there was a wiring harness but I don't know for sure. :dunno

Ok, after looking at a picture and diagram of an e34 without a harness and a diagram of an e34 hu connector, I'm pretty sure mine didn't have a harness to begin with because some of the wire colors listed with the harness I did not see. So far I have been able to figure out that
Blue = Front Left +
Yellow = Front Right +
Brown/Orange = Front Left and Front Right - (There are 2 of then twisted togeather with their corresponding wire)
Blue/Black = Right Rear + (not 100% sure)
Yellow/Black = Left Rear + (not 100% sure)
The Yellow and White from the little white plug are the dimmer/memory, but I'm not sure which one is which and if I need to use both
Then there is a white, brown and white brown wire I'm not sure go to what.
I think the white = power antenna
and I think brown and white/brown are ground/ignition wires but not sure which is which

Any input or clarification would be a great help. Thanks

a way to figure out the speaker wires witch are the haderst usuallly is take a 9 volt battery or drill battery anything like that and put one wire on the negitive of the battery grab your group of wires and touch each and everyone to the postive side of the battery when you come with the right combonation of a matching negitive and positve the speaker will jump fowerd slightly and you no you have the correct wires positive and negitive for that piticlure speaker label the wires with a pen and some masking tape and move on to the next

almost forgot so no one gets mad at me im assuming you no not to touch a positive wire to the negitive on the 9 volt battery weed those at first with a test light witch is very easy

Ok, thanks. The strange things the hu was doing have gone away now that I insulated the chafed antenna wire, so I think I'm just going to follow how the sony one is connected and cap the wires not connected to anything. Also, the stock amp in the back was removed and I got one that I'm going to reinstall so hopefully everything will all work once I get my Pioneer hu and the amp in.