Radio Wiring and Amp Bypass

[Grackle]

First, let me say this is NOT applicable to all E30s. Generally, Late Model (88+) will have this wiring on premium sound cars. IF you have a fader in the dash, this MAY work: you need to unwrap about 8" of fader harness to see if you have 4 pairs of speaker wires, as some cars have only 6 wires, not 4 pairs (8 total) so if this chart does not apply PERFECTLY to your car, don't use it.

Quick disclaimer: this is not idiot proof. You mess it up, don't whine at me, I do not care.

If this saves you countless hours of hassle or you are just feeling generous, feel free to paypal me a tip. Add "@gmail.com" to Stereoinstaller1 and I promise to only use the money for projects on my car.


OK, here is the info.

Obviously, what you do here is simple: connect the "deck" wire to the "dash" wire, then back at the trunk, connect that "dash" wire to the "speaker" wire.

This is not rocket surgery, boys. Get it done.



Aftermarket-----------Dash Wires-----------Speaker Wires

RF+ Grey--------------Blue/Red-------------Grey/White
RF- Grey/Black--------Brown/Orange--------Grey/Brown

LF+ White------------Yellow/Red------------Grey/Red
LF- White/Black-------Brown/Orange--------Grey/Violet

RR+ Violet------------Blue/Black------------Black/White
RR- Violet/Black-------Brown/Orange--------Black/Brown

LR+ Green------------Yellow/Black----------Black/Red
LR- Green/Black-------Brown/Orange--------Black/Violet


(+12V Unswitched) Yellow----Red/Green (Changes to Yellow at C302)

(+12V ACC) Red-------------Violet/White (Changes to Voilet/Grey at C302)

(Ground) Black---------------Brown (may also be Brown/Black)

(ILL) Orange-----------------Grey/Red (Changes to White at C302)

(P ANT) Blue-----------------White (this is one of 2 white wires)

(AMP REM) Blue/White--------White (this is the one in the same harness as the speakers)

Luke

This is driving me crazy. I have my car all apart and I still can't sort this. I don't have any twisted pairs, or the brown/orange wires, nor do I have the blue/brown wires that should be ground. No twisted pairs. I have chased the factory wiring all the way to behind the gauge cluster with no luck. Car has an aftermarket Pioneer deck that was installed at a shop according to the previous owner. Whoever did it capped off all the - outputs from the stereo.

The stereo worked when I bought the car and then quit a couple months ago. If I run a jumper wire from the negative terminal on one of the front kick panel speakers to a negative output from the head unit, all the speakers start to work, though the head unit and the jumper wire gets hot. What in the world is going on here? Car is an 1986es.

ETA: The car has a 6 wire fader in the it.

[Kershaw]

I was given a Continental TR7412UB for my birthday recently and I am trying to install it. I have premium sound, 6 wires, with the fader. The back uses a standard ISO radio adapter, 16 pin.

So my issue is, 1. When I connected my new stereo the same way as my old stereo, it didn't work. My old stereo uses a common ground and 2 leads, L and R. The TR7 uses a ground for the stereo, and then each side/speaker needs a + and -. I've been trying to get any music to play, but I've been having no luck. 2. I misread another thread (that says the same thing about this one, with 8 wires, cut the fader off) and I cut the fader wiring. That's not the biggest deal, I left enough to wire back on if need be, but that's where it is.

So how do I get +/- for each corner and retain the stock amp? Options?

Edit: I removed the amp and ran new speaker cable to each corner. Sounds great.

[tkeenan]

On my car, 9/87 build with premium stereo and fader, I've got a gray/red wire that is constant 12 Volts out of the dash, instead of the red/green as spec'd in the wiring diagram. I do have a red/green wire, I just have no idea where it goes to - it does not go to any of the speakers, and doesn't come out where the amplifier was in the trunk.
My constant dash wire, gray/red, does not kick out 12 volts in the trunk, and the same color is used on the left front speaker, as spec'd in the wiring diagram.
Maybe someone could clarify this for me.

Edit: so I found out that the red/green works for illumination. Strange though. You think it came like that from the factory? The former install looked like a disaster...

[ThatM20Guy]

Are there any common spots for the radio wire to short out at?

Recently went to install my new headunit, a JVC 775s, and it keeps giving me the error message -Misswire, check wiring then power on.

Every time i turn the headunit on there is a pop at the rear right speaker then it proceeds to give that error code. I am positive that it is a short in the wiring but I really don't want to pull all the wiring if I don't have to. No possibility of a short at the headunit connections because all of it is connected and electrical taped off. Any ideas?

[tkeenan]

Once those are out, keep unwrapping, you will find a point just past the "branch" where the grounds junction. The two left grounds are connected to a brown/black that goes to the fader, the two right ground do the same.

So, once you unwrap the harness, you should find those two ground junctions, cut them so the wires are as long as possible.

Once you have those ground junctions you should have 8 speaker wires behind the deck, so no need to run wires at all.

Next, lets talk about the tweeters...first, are you using Premium mids with them? If not, what are you using as a passive crossover? Some form of passive crossover is a necessity, the stock Premium setup has that crossover built into the midwoofer, thats why it has 4 terminals.

HTH
Luke

I think I'll just run new wire to the front speakers. I don't really understand your explanation. I'm I understanding that I can have 8 speaker wires behind the dash. Whereas, I thought I only had 4, which are repurposed ones anyway - the ones from the fader to the amp.
My original question was whether or not I could pull the soon to be useless old front speaker wires and re-route them. Just being cheap as I don't want to have to go buy new speaker wire if I can get some good ones for free. I already messed with that a little and realized it's not worth my time.

I've the tweeters in the door. I think I'll reuse them. Actually, I hope I can reuse it, and all my other speakers minus 1, as since I bought the thing in 2010 I've only been listening to talk radio out of one speaker. The election talk pushed me over the edge though.

[Grackle]

Hi, I have a problem with my 86 325es.

Shortly before I bought my car from the previous owner, he had a new stereo installed. A few months after I bought it, the rear speakers stopped working consistently (not sure if the fronts ever worked). However they would start giving me sound after a few minutes of driving. Now they are dead completely.

I pulled the stereo and jumped some temporary wires to a spare speaker I had on hand. It worked, I was able to hear music playing. Someone told me it is possible that my amp has gone bad and that is my problem. Does this sound correct?

Thanks

[StereoInstaller1]

My car is a 9/87 build date, with 8 wires coming from the fader (premium sound), so for my case, running new wires to the front and repurposing wires for the rear speakers was suggested.

88 and 89 were likely equipped with the dash mount fader, that means front and rear speakers are wired to share a ground (its "negtive" BTW, not "ground", just so you know) on each side, and that isnt acceptable for an aftermarket deck.

The trick is this: you have to have 8 speaker wires behind the deck. If you don't have 4 pairs of wire, its not going to work right. Read your install guide, this applies to all modern decks.

So, what to do?

On the super early cars (84/85) the ground junction is under the front seats, on somewhat later cars that junction is inside the dash, on much later cars (like yours) that ground junction is in the harness about a foot down the harness.

So, 88-90, pull the harness out of the dash about 18", (meaning you may have to untangle it from the rest of the dash harness to get enough out) and unwrap it.

Once you get enough unwrapped, you will see the solid yellow (gelb) and solid blue (blau) only go from the deck to the fader, so remove those.

Once those are out, keep unwrapping, you will find a point just past the "branch" where the grounds junction. The two left grounds are connected to a brown/black that goes to the fader, the two right ground do the same.

So, once you unwrap the harness, you should find those two ground junctions, cut them so the wires are as long as possible.

Once you have those ground junctions you should have 8 speaker wires behind the deck, so no need to run wires at all.

Next, lets talk about the tweeters...first, are you using Premium mids with them? If not, what are you using as a passive crossover? Some form of passive crossover is a necessity, the stock Premium setup has that crossover built into the midwoofer, thats why it has 4 terminals.

HTH
Luke

[tkeenan]

My car is a 9/87 build date, with 8 wires coming from the fader (premium sound), so for my case, running new wires to the front and repurposing wires for the rear speakers was suggested.

[s1uma1]

Just wanted this clarified, as several times it was mentioned that running new wires to the fronts on a premium sound 88+ car is easier.

Okay. Im probably confused bc read earlier in a few threads that it was best to keep the stock wiring, I think this was from Luke? was that only intended for pre-88 cars? Either way, I may borrow a friend's head unit and see if any difference...

[tkeenan]

Just wanted this clarified, as several times it was mentioned that running new wires to the fronts on a premium sound 88+ car is easier.

[s1uma1]

How hard is it to pull the front speaker wires that come from the amp, separate them from the loom of wires, and then rewire them directly from deck to front speakers?

Not hard. My car doesn't have an amp so it's probably even easier. But having tried all the outputs, the front premium speakers do t sound as good as the aftermarket eclipse speakers... I was under the impression that the premium speakers would best any aftermarket speaker of the same size. That's why I wasn't sure if it's a wiring issue or a head unit issue

Thanks for your suggestion though

[tkeenan]

How hard is it to pull the front speaker wires that come from the amp, separate them from the loom of wires, and then rewire them directly from deck to front speakers?

[s1uma1]

Hi Guys. i have a 91 318is. Non-premium audio. Original Alpine Headunit (slider unit). I recently wired up a pair of premium speakers for the front (tweeters and mid drivers). Hooked everything up and it sounds like absolute ass. I read through this entire thread "Radio Wiring and Amp Bypass", but seems like mostly directed at premium audio folks. Saw a few posts were it was stated 91 Base systems should be very easy. Trying to figure out if 1) wiring issue 2) speaker issue 3) head unit issue.



Here's the back of my head unit... and i labeled what i think the wires are:


Here's how the tweeters are wired


so when i hook up the speakers correctly into the headhunt, i have almost NO sound coming from the front. Rears sound great. The fade/balance function on my headhunt does crazy things... fading to front cuts out front volume, but i still hear rear speakers.

When i REVERSE the connection, (front wires to rear output and rear wires to front output), the fronts have sound, but sound like ass. mid bass driver is firing, tweeters are going, but little to no bass and easily distorts at moderate volumes.

Any suggestions/advice?

[StereoInstaller1]

87 Vert means you need to run new wires to the front speakers and re-purpose the input wires to the rear speakers

[AngeloF10]

There are 8 wires that come out of the fader, two of which are the yellow and the blue I mentioned above. No twisted pairs anywhere. Now I am really losing it