head unit wiring + fader delete

[Drew325is]

Hi All,

I have had a Nakamichi CD-45Z head unit in my E30 (my E30 has the basic BMW sound system - no amp etc) for ages now, but I've got it out for the moment and thought I'd change some wiring around. It's currently wired so that only 2 of its channels are connected, and running through the E30 fader on the dash. The fader is getting very crackly now, so I thought I'd ditch it and use the head unit's fader instead. I don't want to re-wire the whole the system, so can I wire into the existing speaker wiring as so:



My main question is regarding the grounding of each side of the system. Can I wire it as above without any issues such has alternator buzz etc?

Cheers!

[357]

General wisdom is that you don't want a common ground between two speakers. The amp isn't generally designed to have a common ground between any two speakers, since its not a DC system, and has the ability to independently drive the voltage level to each speaker.

When I did my install, I ran all new wiring to each of the four corners, and to my sub. Wasn't really all that difficult.

[digital_cowboy]

If you are planning on using the head unit to power the speakers for a while (I mean no amp install), I agree that running new wire is the way to go. Its really not that bad at all.

[Drew325is]

Thanks for the input guys...I think I'm settled on a partial re-wire...I'll just run new grounds to the front, and use the existing ground for the rear. I'm pretty confident that even with just minimal re-wiring, ditching the fader, and getting all four channels going from the HU, I'll be a long way ahead of where I'm at now. Cheers!

[StereoInstaller1]

OK, stop right there.

If you have a non premium sound car, you do not need (nor would I recommend) to run new wires...everything you need is already in the dash.

That diagram you made in the OP is WRONG, and will smoke your deck after a while, plus it will sound really shitty.

Ask "Danny" what a difference it made, I did his in 15 minutes while we were at the Picnic.

Here is what to do:

1. Remove deck
2. remove fader
3. unwrap wires to the fader, about 8 to 10 inches before the plug.

You will find 2 sets of 3 wires, all brown, or like brown/orange.

These are your speaker negatives.

Now, use yellow/red for the left front positive and the wire it is twisted with is the ground for that speaker.

Yellow/black will be the left rear positive, the twisted wire is the ground for that speaker

Blue/red is right front, again with the twisted wire thing...bet you see the pattern now, dont'cha?

Seriously, if this takes you half an hour, I would be amazed.

You will also see how the 2 blue wires feed into the fader, and the chassis ground.

If you see a grey/red wire, that is the dash light circuit. Cap it off, you won't need it.

BTW, the stock 20 year old BMW wire is excellent, use it in good faith.

[Brian 89 325i]

Wow, I may have found a new Project for after work on Weds. Thanks Luke

Brian

[StereoInstaller1]

Wow, I may have found a new Project for after work on Weds. Thanks Luke

Brian

Do yourself a favor and buy some Channel Lock crimpers.

Excellent and about $20 at Home Depot.

[Drew325is]

OK, stop right there.

If you have a non premium sound car, you do not need (nor would I recommend) to run new wires...everything you need is already in the dash.

That diagram you made in the OP is WRONG, and will smoke your deck after a while, plus it will sound really shitty.

Ask "Danny" what a difference it made, I did his in 15 minutes while we were at the Picnic.

Here is what to do:

1. Remove deck
2. remove fader
3. unwrap wires to the fader, about 8 to 10 inches before the plug.

You will find 2 sets of 3 wires, all brown, or like brown/orange.

These are your speaker negatives.

Now, use yellow/red for the left front positive and the wire it is twisted with is the ground for that speaker.

Yellow/black will be the left rear positive, the twisted wire is the ground for that speaker

Blue/red is right front, again with the twisted wire thing...bet you see the pattern now, dont'cha?

Seriously, if this takes you half an hour, I would be amazed.

You will also see how the 2 blue wires feed into the fader, and the chassis ground.

If you see a grey/red wire, that is the dash light circuit. Cap it off, you won't need it.

BTW, the stock 20 year old BMW wire is excellent, use it in good faith.

First up, thanks for the heads up regarding the original diagram I proposed...that was just the thing I was worried about.

Now regarding the existing wiring...with reference to the diagram below...you're basically saying the the splices S313 and S403 are located about 8-10inches back from the fader plug? That's handy if I've interpretted your post correctly. Should be pretty easy to deal with.


EDIT...hell yeah, just found them...that's too easy! Thanks for the tip!!!!!!

[StereoInstaller1]

EDIT...hell yeah, just found them...that's too easy! Thanks for the tip!!!!!!

Cool...now go take a picture of them to show R3V how to deal with this!

[menusk]

I'm doing this shiz today also! Good stuff

[Drew325is]

Cool...now go take a picture of them to show R3V how to deal with this!

I'll snap a pic tonight and post it. Thanks again for the help.

[toffa182]

I just removed the fader in my car and split the grounds. Connected everything else and fired up the stereo. Heard a crackling sound...so I started troubleshooting. I noticed that the rear speakers played with only the positive lead connected, which meant they we're grounded elsewhere (WTF).

I followed the speaker cable harness and then, lo and behold, there was a connector somewhere above the front left speaker. What I found odd, was that there were only six pins on the connector (WTF?). So it turns out that the grounds that I had just split after the fader connector, were once again connected to each other. On top of that, after the connector the grounds were again split! (WTF!)

I'm just going to bypass the connector.

(Mind you, I live in Finland and have a European 1989 320i Touring. It might not be the same on your car.)

[menusk]

on the left hand side of the picture you can tell the grounds are spliced together when they are coming out of the harness. i cant see what the other end looks like. but there should be two yellow wires with brown stripes. now do them one at a time.

yellow wire w/red stripe = left front speaker. drivers side. hook it to your stereo, now hook up one of the yellow wire w/brown to your stereo also. do one at a time untill the front drivers side speaker turns on. so on and so forth. i did mine and dam it sounds good.

red stripes are front speakers and black stripes are rear speakers. brown stripes are the grounds, you need to find four. yellow wires drivers side. blue wires passenger side. all this is assuming you dont have premium sound cause that might be different

oh yea and on my stereo it didnt have those splice caps like the picture above. they were more like crimped together and i had to get in there real deep, unwrapping the tape. i even had to cut the big zip tie that holds that wire up becuase they were further past that point.

[toffa182]

on the left hand side of the picture you can tell the grounds are spliced together when they are coming out of the harness. i cant see what the other end looks like. but there should be two yellow wires with brown stripes. now do them one at a time.

No need telling me, I know my stuff ;)

I just wanted to give a heads up; in case you have the connector I do (shown in the picture above), then StereoInstaller1's intructions only partly apply.

[Drew325is]

Well I just finished the fader delete a-la-Luke and gave it a quick test run...AWESOME...so worthwhile. I'm amazed I left the poor Naka deck wired up so sub-optimally for so long.

2 channels splt amongst 4 speakers via factory fader = fail
4 channels for 4 speakers = WIN!

Thanks for the help!