Radio Wiring and Amp Bypass

[Ken o]

Great thread! This really helped me and my son install his system.

Two questions. Everything is working but the power ant and power from the Red/Green in the dash. We are using a different power source for now. I am getting power for the ant from the Alpine unit. We had an OEM radio that was working off the OEM wire and the ant worked.

1986 325es, 10/86 build date, Premium sound, rears on BMW wire, fronts on new wire, Alpine unit.

[CB-M3]

^ You are in the same boat as me. I have 318is with premium. Did you install your pioneer unit yet?

[JonnyOg]

So would my system sound better without the factory amp? I'm just using the pioneer head unit you recommended.
Premium sound 91 318is

[CB-M3]

I took out the amp today and looked at the wires in the trunk. Got all the wires identified for between amp and speakers but still not sure on a few wires to head unit. See pic. Basically I'm going to connect all the RF+ to RF+ and LF+ to LF+ and so on. I'll see what's left after I do that.

1) I have 4 wires (2 yellow/brown and 2 blue/brown) that join up to 1 Brown/Black wire. These are the Left and Right channel ground at AMP end only. What do I do with these? Is this what people mean by common ground? Leaving the booster amp to speakers I would need to provide ground via the (2 yellow/brown and 2 blue/brown) from head unit? For instance there are 2 yellow/brown for Left Channel Ground but how do I know which one is Left Front and Left Rear?

2) What do I do for the 12V wires?

3) Do I need the solid Brown Wire (ground)? Connect it to the 4 to 1 Brown/Black wire?




BETWEEN HEAD UNIT AND BOOSTER AMP

Yellow/Red - Left Front Channel
Yellow/Black - Left Rear Channel
Blue/Red - Right Front Channel
Blue/Black - Right Rear Channel
Yellow/Brown - Left Channel Ground at Amp End Only
Blue/Brown - Right Channel Ground at Amp End Only
Brown - All Channel Ground at Head End Only
(note that the all of the grounds are spliced together within the wiring harness - the system uses a common ground between the head and the amplifer)
White - 12V Switched (to turn amplifier ON when head unit ON, also runs to power antenna)

BETWEEN AMP AND SPEAKERS

Pair: Black/White and Black/Brown - Right Rear Speakers
Pair: Grey/White and Grey/Brown - Right Front Speakers
Pair: Black/Red and Black/Purple - Left Rear Speakers
Pair: Grey/Red and Grey Purple - Left Front Speakers
(note that the wires highlighted in red above all run to the crossover side of the midrange drivers, you'll want to know this to keep all your speakers in phase - make sure all of your speaker (+)s go to these wires)
(also note that the speaker circuits DO NOT use a common ground when they leave the booster amp)

[StereoInstaller1]

can you take pics of the cut and connect at the rear seat?

The pics you are looking for are in this thread....good luck, I created a monster!

[CB-M3]

Got it, thanks.
I will do the install tomorrow morning!

can you take pics of the cut and connect at the rear seat?

[redhotchilipepper]

Got it, thanks.
I will do the install tomorrow morning!

[StereoInstaller1]

and yes I know, there are more tutorials needed...

[StereoInstaller1]

YES!

Holy crap, yes, that is exactly how it is done.

Do that connection behind the back seat and "re-purpose" just like your diagram shows.

If you get stuck, hit me up...but I think you got it.

Luke

[redhotchilipepper]

Okay I have drawn it up for you, hopefully you can see my cruddy upload:

This is what my current wiring looks like:


And this is what I would like to do, so as to run a minimal amount of wire:


There may be a better way to do this, but I definitely want a ground for each speaker. Thanks for the help.

[benyen soljax]

Draw a diagram in paint, this doesn't make sense. Running new wires for the front in the non-premium cars I think is because you don't have enough ground wires with the stock wiring. So instead of using one ground per side or whatever, you use the stock grounds for the rear speakers and then wire up new stuff for the front. I could be wrong and I haven't played with the e30 wiring extensively.

The premium wiring sure does make this a whole lot easier, just snip the back and connect them together or to an amp and done.

[redhotchilipepper]

Could someone tell me if this will work okay in my non-premium '85 318i?

All stock wiring, as follows: (behind the dash):
A single Yellow/brown (left side ground, I believe)
A single Blue/brown (right side ground, I believe)
Yellow/red (FL +)
Blue/red (FR +)
Yellow/black (RL +)
Blue/black (RR +)
The usual power, memory, and illumination wires
Fader, which I bypassed and removed a while ago to put another switch in the dash

Alpine CDE-9845 head unit
Stock 5.25" front speakers (non-premium I guess?)
Premium "boxed" speakers on the rear deck (from junkyard)

I am about to install a Planet Audio 1800.5 amp and LukeBox with an Infinity 1062w subwoofer. I read through the 13 pages of posts and it sounds like i need to use the rear stock wires for the rear speakers, and run new wires for the fronts. HOWEVER: why can't i cut the 2 pairs of rear wires at the "halfway" point behind the back seat and then use the rear half of my split to power the rears, and the front half of my split to power the fronts (rear wires connected to front wires behind the dash)? That way I don't have to run as much new wire! Thought I'd ask you pros before attempting.

[StereoInstaller1]

why did you have to run new wires for the 2 front speakers instead of using stock?

In his case, being early premium and using deck power for all 4 corners, the logical thing to do is use new wire for the fronts.

Had he used an amp, no wires would be necessary, but since there are 4 wires to the amp, they can be "re-purposed" to be rear speaker wires.

The nice thing about this setup is being able to convert to using the stock wire and an amp if so desired.

Make sense?

Luke

[CB-M3]

why did you have to run new wires for the 2 front speakers instead of using stock?

[StereoInstaller1]

Gotcha...perfect