Understanding E30 speaker and amp wiring

[bradnic]

winterse30 that's a wide open question, very hard to answer. I assume this is a factory radio setup. if you can pull your radio to access the speaker wiring, try swapping the left and right speaker wires. If the working speakers change to the other side then the problem is your radio. if the same speakers still don't work then it's not the radio. You just need to keep isolating stuff until you figure out where the problem is. good luck

[bradnic]

I updated the original post with more info, including an example of a two channel radio amp bypass. the 2 channel radio BMW sound system setup has fewer wires going to the power amp connector than the 4 channel setup.

[quasi mofo]

Here is a standalone picture of the 2 to 4 channel adapter, part number 61101388934

Note that there are no ground wires in that harness.

Can this adapter be deleted and the in dash speaker wires run directly to the head unit? The PO of my car just the far end "LH" and "RH" labeled cables and used butt connectors to run them to the head unit. The green/black and purple/black negative left and right rear speaker wires connected to this second harness. The positive green and purple wires aren't connected to anything. Currently still only have sound to the right tweeter, left tweeter and left front and rear speakers.

I still want to use the stock wiring so I don't have to pull apart the interior again, but at this point maybe I should just delete everything and run my own cables.

[bradnic]

quasi mofo sounds like you are going aftermarket. Just head over to the stickied @stereoinstaller wiring thread in the same audio forum

that harness adapter is the rear speakers only on cars with premium sound and 4 channel radios.

you will also have a blue and a yellow wire with a speaker connector on it. Those are the positive leads for the front speakers

Drop me a PM and I’ll be happy to buy the wiring bits you remove from you

[CW325]

On an early model 2 channel radio only car would I need a “floating ground adapter” or could I just share the front/rear negatives for each side?

[CW325]

On an early model 2 channel radio only car would I need a “floating ground adapter” or could I just share the front/rear negatives for each side?

Update: after doing some more research I ran new negatives for the 2 front speakers and left the existing negatives as dedicated rear negatives.

[ave30rudy]

so I did all the new head unit wiring, all the speaker wires connected to the new speaker wires, and power etc. Then I have one yellow wire and one blue wire, both coming from the power bundle, not the speaker bundle that have no where to connect to. I went ahead and did the whole amp bypass wiring as well. However I still have no sound. My assumption is that my problem is coming from those two wires in the dash. But my question is where do I connect those?

[bradnic]

ave30rudy did you figure it out? info is in the schematics above. if you ended up with one solid yellow and one solid blue wire unconnected, then you have not connected the head unit to the speakers. From your description it sounds like the two wires are at the trunk amp connector.

[bradnic]

...a class D 4 channel amp could potentially fit in the original amp housing. It’s a lot of work though. You can accomplish the same thing with an amp bypass and wiring in a small commercial class d amp. It does require cutting the harness though. The key issue is sourcing the connector on the amp housing. I haven’t been able to find it yet.

If you can't find the stock amp connector anywhere, you might consider replicating it in CAD and 3D printing it.

There are lots of places to get high quality 3D prints now a days. Stratasys, Xometry, ProtoLabs to name a few.

RyanBelton is offering a 3d printed connector that you can use to make an aftermarket amp harness with.

[bradnic]

just received my power amp connector from RyanBelton . It is very well made and documented. Highly recommended.

[nando]

Man, I fee so stupid for hacking up my original wiring and putting in a shitty aftermarket head unit (long since gone - I've had a blank plug in that spot for years now).

Thinking it might be time to go back to all OE. All of the wiring is still there I think, but I don't remember exactly what I cut and removed. I gave away the stock premium radio for a song too! But it looks like I still have options. I'm pretty sure I left the amp inside the car (I hope!). I actually have a full harness from my '88 ix parts car, but that had been cut a bit as well.

edit: well, apparently 21 year old me wasn't as dumb as I thought. I did cut a couple wires - but I actually left all of the original harness and plugs there. I remember now - ran separate wires from the stereo to the connector in the trunk, so all of the wires to the speakers, head unit, etc are original and untouched.

http://www.325ix.com/photos/cache_big/2021/OE%20Stereo/IMG_2133.jpg
http://www.325ix.com/photos/cache_big/2021/OE%20Stereo/IMG_2134.jpg
(looks like image linking is broken on this forum now, ugh)

The bad part is I can't find the amp (it's not in the trunk). I thought I had it somewhere, but I dug through my giant pile of parts and didn't see it. There's a spider infested box I haven't looked at in years, it might be in there, but it's probably water damaged by now anyway.

At least repairing the original harness should be dead simple! All I have to do is remove the butt connectors and splice the stock wires back together. I'll probably want to pull out those speaker wires I put in, but they aren't hurting anything if I just leave them either.

[bradnic]

nando !!!!! damn son. Happy to help get your setup back. this is your IX right? you've got premium sound I think.
if you want the wiring back 100% stock just hunt on ebay. Otherwise I have some of jay's repair connector kits.

[nando]

yeah, it's my ix, it had premium sound - but I have no recollection of what the original stereo was (might be able to find it in old pics). I think I can just repair the wiring, but I might be missing a pigtail/adapter or whatever was plugged directly into the stereo.

actually, I have *one* pic of the stereo (sorta) - from the day I got the car in 2002, lol:

http://www.325ix.com/pics/2002/05-31-02/MVC-272F.JPG

[bradnic]

That’s a KE83ZBM 4 channel pioneer. Switch to a 5908 slider and you can rock the Canteloupe BT board. Jay’s not doing them anymore but I am doing another production run later this summer.

[bradnic]

BTW you’re missing the 2 to 4 channel adapter harness. Pic and part number earlier in the thread.

nice job keeping the original connectors and just splicing in the ISO bits for your aftermarket. I did the same thing on my vert years ago so it was super simple to restore it back