View Full Version : New head unit in E30...

eta Epsilon
03-21-2009, 05:43 PM

I'm installing a new HU in my E30. I have the premium sound system. Well I think I have it since I have the twitters where the mirrors are.

I got every cables connected except the ground wires for the speakers.

From what I can understand, there is suppose to be a Yellow-brown and a Blue-brown wire. These are the grounds. The problem is that I don't find these 2 wires...:eek:

Is there another way to ground the speakers? Can I run a wire from each speaker and just ground it to the nearest metal components?

The weirdest thing is that I removed another aftermarket radio from that car and the radio was playing just find.

I'm really confused :confused:

Please help me!



eta Epsilon
03-21-2009, 08:33 PM
come on peoples...

If I would connect the 4 ground wires to the main ground of the head unit, would it work?

03-22-2009, 12:46 AM
if a head unit came out previous to this one all you have to do is match the colours from the harness from before to the one you had now.......unless its hard wired and you cut the wires?

eta Epsilon
03-22-2009, 07:15 AM
The problem is that I thought the wires where "standard" like in the other cars where I installed HU, so I did not really look at how the previous owner had connected the wires...


03-22-2009, 07:34 AM
If you have premium sound, it is best to by-pass the stock amp located in the trunk.

Just re-run new speaker wires from the deck to each speaker.

Attempting to use the stock wiring for a preium system will only make use of one speaker channel, because the stock premium sound only sends one line output to the amp in the trunk, then it is wired to each speaker from there.

No easy way around it if you want to do it right.

if a head unit came out previous to this one all you have to do is match the colours from the harness from before to the one you had now.......unless its hard wired and you cut the wires?

Bad advice. Colour codes almost never match.

eta Epsilon
03-22-2009, 08:12 AM
Yeah, that was my next step...
Damn, looks like fun...

eta Epsilon
03-22-2009, 11:44 AM
OK, here what happens now,

I have the fader thing. I've remove the wires coming out of it. Now I have a power wire for each speaker.

I've connected the "power" wire of each speaker to the correcponding wire in the radio harness.

Now, I need to connect the grounds. The problem is that there is 2 "grounds" and 2 "power" on the front right speaker (it's the only one I have work on so far)...

Here a picture.
I installed the connector "3" to the ground "1". I have also tried to connect the ground "5" with the the preceding wires. I got sound, but there is always a very loud craking sound comming from that speaker.

By the way, wire "2" is the "power" for the speaker. The wire "4" wasn't connected, or maybe it got disconnected when I removed the speaker.

I'm really confused.
Anybody can help???


03-22-2009, 11:53 AM
What happens if you connect the pos and neg from one channel of the deck to ONE SET of the pos and neg on the speaker?

I am confused as to why that speaker has two sets of pos and neg.

eta Epsilon
03-22-2009, 12:14 PM
i don't know. I could try.
I wonder if the second set of pos and neg are not re-route to the tweeter...

eta Epsilon
03-22-2009, 05:10 PM
ok, I've connected the ground wire (direct from the radio) to connector "4".
No cracking sound, but sound quality is poor. Lot of "waving" in the sound.

Damn I'm pissed! The other aftermarket radio that was in the car was working!!!
I will try to contact the previous owner to see if he installed the last radio himself.

If not, I'm F**king bring it to a sound system installer!

03-22-2009, 06:28 PM
The reason for those connections in the kick panel speaker is because it has a built in cross-over for the tweeter (to only allow highs going to the tweeter).

It's to complicated to explain in words, but the direct connections goto the speaker, the two wires coming out of it, containing the cross-over loop goes to the tweeter (that is probably why that wire is sliced and cut off).

If you already had an aftermarket deck then, im not sure what kind of hack job could have been done or even if your sound system was wired for premium to begin with or if it was added.

Is there a stock amp in the trunk where the power attenna is?

eta Epsilon
03-22-2009, 06:45 PM
I think i'm trying too hard.
the other aftermarket radio that was there before was working.
theorically, I shoulnd have to cut and splice wires...

i will sleep on it, or at least try. it kept me awake for a while last night!!! :-(

03-24-2009, 03:05 PM
lol im pretty sure weve all done that at one point. Its all a learning experience. ill look to see if i have a wiring diagram at home for the radio. if not i would re-wire the speakers(by pass the amp).

03-24-2009, 08:31 PM
i was all confused with mine but i searched for installing aftermarket radio in google for the car and i found the wires that you need to snip and conect to gether that bypasses the stock amp. then there are wire that you need to find in the dash and just add some conectors to it and boom your done ill check and see if i can find the site again

03-24-2009, 08:33 PM
see if this helps


eta Epsilon
03-28-2009, 05:13 PM
I finally took the time to re-wire all speakers.
I re-run wires from the radio to each speakers.
It took me about 2 hours. I did splice on every wire (no tape here!)
it was maybe not needed, but it can't hurt to replace that 20 years old wires.

Everything works!

eta Epsilon
03-28-2009, 06:05 PM
Once everything is ready to go back in the dash

The old speakers are out and the new are in

All rear speakers removed

I bought the radio from my girlfriend. She had it in her car for about a year. It still has the plastic protection on top.:eek:

Not a pro install, but it works.*rockout*
Thanks to all who gave me advices!*th-up*

03-28-2009, 06:58 PM
lol you're an animal......i installed a couple speakers today and realized that my deck install was done using the factory amp. Amazing sound from the bmw premium sound system especially for 1987!

eta Epsilon
03-28-2009, 08:04 PM
Yeah the sound was good with the amp, but it's better without!