The official e30 Aftermarket Radio Install Write up!

[Snarcher!]

If you have the premium system ( tweeter on doors, plate speakers on rear deck )

• Yellow wire from new head 12v+ goes to Red/grn in dash
• Red wire from head ign goes to purple/wht in dash
• Black wire goes to brown wire in dash plus two extra brn/blks that were attached to old head. There will be three wires total hooked to the black from new head.
• Blue/wht from new head goes to both white wires in dash. If you don't have a blue/wht on new head, use the blue.
• That will leave three wires:
• If your new head has a dimmer lead ( usually orange ) it will attach to the red/grn lead in dash. If the new head does not, TAPE THIS OFF. No sense blowing fuses now when you are so close to sound.
• White wire from new head goes to yellow wire in dash
• Grey wire on new head goes to blue wire in dash.
• Tape off ALL REMAINING WIRES FROM NEW HEAD, don't allow them to touch each other or any metal in the dash.
• This uses the factory fader, and factory amp, without messy rewiring.
• Anyone who tells you that the new radio has more watts than the old amp needs to look at what it takes to make 40x4 rms. It sure ain't gonna fit inside a deck, and it will need at least 10ga power wire, which new radios don't have.
• I worked the install bay many many years. I did every e30 like this, and my 88 535is has had this wiring for 6 years, no problems. There is a common thread on these boards that says 'rewire' when it is not needed.
• If you have the std system without an amp, it is just as easy, there are two extra wires. Email me for details if so.
• If you are confused, take it to a reputable shop ( no Best or Circuit in the name ). 40 bucks and you will be in and out in 10-15 minutes.

its 12am here and I'm tired and bored. The proper illumination wire found in the dash of e30's is Red/GREY not Red/grn as I said. So shoot me, lol.

[Bimmer Ese]

Great write up. It took me a while to figure out the wiring (with the amp) when I wired a CD43 into my car.

Hopefully, some of the other board members will benefit from this.

Dan

[Antrieb]

If I buy a deck can you help me install it?

[e30es]

Perfect Timing!! Doing my install this weekend....=)

[Snarcher!]

this is the one i used to do mine, just thought id share

sure annie, what one you getting? Alpine FTW

[Antrieb]

this is the one i used to do mine, just thought id share

sure annie, what one you getting? Alpine FTW

Do you have any extra ones lying around?

[Snarcher!]

No,

[Antrieb]

Hey Brian repost this in the DIY section that is stickied on top of the e30 section. linky

[318iEnthusiast]

damn i wish i had that 2 months ago... i spent 6 hrs trying to find a decent write and still didn't find a good one...

[mizer]

Which color wires are for the corresponding spekers?

[e30blitz]

And fast forward to the year 2013

Bump from the past


OO ||| OO + O w O

[540ig5]

Just installed mine using the above write up in all of 8 minutes. Works great, awesome sound. Thanks.

[CMG]

Can't u just get an adapter so u don't have to cut the wires in the first place?

[clemjonze]

Nice! Wish I knew this last year. Bought a new Kenwood for the old '88 325I. The installer took all day and BROKE the in dash computer in the process! Pisser. He told me he'd done lots of older BMW's. Should have done it myself.

[Eturdee]

If you have the premium system ( tweeter on doors, plate speakers on rear deck )

• Yellow wire from new head 12v+ goes to Red/grn in dash
• Red wire from head ign goes to purple/wht in dash
• Black wire goes to brown wire in dash plus two extra brn/blks that were attached to old head. There will be three wires total hooked to the black from new head.
• Blue/wht from new head goes to both white wires in dash. If you don't have a blue/wht on new head, use the blue.
• That will leave three wires:
• If your new head has a dimmer lead ( usually orange ) it will attach to the red/grn lead in dash. If the new head does not, TAPE THIS OFF. No sense blowing fuses now when you are so close to sound.
• White wire from new head goes to yellow wire in dash
• Grey wire on new head goes to blue wire in dash.
• Tape off ALL REMAINING WIRES FROM NEW HEAD, don't allow them to touch each other or any metal in the dash.
• This uses the factory fader, and factory amp, without messy rewiring.
• Anyone who tells you that the new radio has more watts than the old amp needs to look at what it takes to make 40x4 rms. It sure ain't gonna fit inside a deck, and it will need at least 10ga power wire, which new radios don't have.
• I worked the install bay many many years. I did every e30 like this, and my 88 535is has had this wiring for 6 years, no problems. There is a common thread on these boards that says 'rewire' when it is not needed.
• If you have the std system without an amp, it is just as easy, there are two extra wires. Email me for details if so.
• If you are confused, take it to a reputable shop ( no Best or Circuit in the name ). 40 bucks and you will be in and out in 10-15 minutes.

its 12am here and I'm tired and bored. The proper illumination wire found in the dash of e30's is Red/GREY not Red/grn as I said. So shoot me, lol.

Hey, what about the rear speakers, where do I connect them?

[richardodn]

Hey, what about the rear speakers, where do I connect them?

First of all, this thread does not completely apply to your situation. A '91 would have had a 4 channel factory head unit and not 2 channel with fader. Secondly, he makes a couple of choices which are non-optimal. Is your car equipped with a factory amp?

1. The above description is for the early premium system 2 channel head unit and external 4 channel amplifier. The original wiring for this arrangement used yellow (left) and blue (right) signal wires which are then split at the fader wheel into 4 signals (LF, LR, RF, RR) that run to the amplifier. Return is through chassis ground. These are the brown/black wires. (Original wiring in BMWs for this era use brown as a standard ground color.) Wiring the system in this way usually works, unless your head unit can't tolerate the common ground. This method makes the fader control in the new head unit non-functional. Instead it is still controlled via the fader control in the dash. Personally, I'd bypass the fader in this arrangement and connect all 4 signal wires to the corresponding wires post-fader. You'll leave the head unit speaker black stripe wires all unconnected. Instead the signal return path goes through chassis ground.

In this case the post-fader colors should be:
yellow/red (LF) connects to head unit white
yellow/black (LR) connects to head unit green
blue/red (RF) connects to head unit gray
blue/black (RR) connects to head unit purple

2. For the case with the later factory 4 channel system and factory amp where you still want to use the factory amp, you basically do this the same as bypassing the fader above.

3. If you choose to bypass the factory amp, you need to run all new pairs for the speakers and wire the speakers as specified by the head unit manufacturer.

4. Finally if you are wiring a car that did not have a factory amp, you'll have 4 twisted pairs that run to or near the head unit location. Sometimes you'll have to cut back the harness wrap a bit to find them. Each pair is a +/- set with the signal wire color as described above and the brown stripe wire the return ground. Wire the speakers as specified by the head unit manufacturer.

[rjcaptsean]

Silly question;

How do you know if your car came with a factory amp? Is it bolted to somewhere obvious, like the in the trunk bolted to the rear wall?

[richardodn]

After reading some posts in the audio forum, here's my understanding of the reasons for ignoring the head unit's speaker grounds and instead using chassis ground. The factory amp uses a speaker level input from the original head unit. Replacement head units typically have a much higher speaker level output than the factory deck. My understanding is that most decks use a BTL (bridge tied load or simply bridged) amplifier chip for each channel. Just like bridging an external amp, the plus side goes more positive in response to a louder signal while the minus side goes more negative. The overall difference between the two provides more power, just like when bridging an external amplifier. (Note that this is not a balanced differential arrangement.) When you tie the channel's return path to chassis ground, you effectively halve the power output from the head unit since the reference is to ground.

As an example to better understand this, suppose the amplifier channel is outputting +1 on positive and -1 on negative. This gives you an effective amplitude of 2. When referencing to ground, you get +1 on positive and 0 on negative resulting in an effective amplitude of 1.

- - - Updated - - -

Silly question;

How do you know if your car came with a factory amp? Is it bolted to somewhere obvious, like the in the trunk bolted to the rear wall?

Yes the amp is mounted in the trunk. I'm not exactly sure where it is on the E30. In the E28 it just hangs from the back shelf in the trunk. Even easier is to look at your speakers. Assuming the car is still stock, the premium system would have the tweeter pods in the door and 2 way speakers on the rear deck.

[rjcaptsean]

I have the tweeters in the doors, but that pesky rear shelf is non-existent. Definitely no amp bolted to the rear wall of the trunk. (It's a convertible)

[RomeoMike]

A few thoughts:

A VIN lookup service would help in determining if it came with premium sound from the assembly line. It's possible the tweeter pods were retrofitted (did that with my 91, haven't finished hooking them up yet). If you pull back some of the gray trunk liner in the vert (below the longest side of the trunk lid gasket) that's where you might find the factory amp.

[shawnkhanobi]

nice walk through but on some cars the ground wires will be brown, yellow/brown and then a blue/brown and you would connect those 3 to the black wire on the head unit. those 3 wires are the grounds on my 1985 325e. it has the premium sound system.

[iklektic]

If you have the premium system ( tweeter on doors, plate speakers on rear deck )

• Yellow wire from new head 12v+ goes to Red/grn in dash
• Red wire from head ign goes to purple/wht in dash
• Black wire goes to brown wire in dash plus two extra brn/blks that were attached to old head. There will be three wires total hooked to the black from new head.
• Blue/wht from new head goes to both white wires in dash. If you don't have a blue/wht on new head, use the blue.
• That will leave three wires:
• If your new head has a dimmer lead ( usually orange ) it will attach to the red/grn lead in dash. If the new head does not, TAPE THIS OFF. No sense blowing fuses now when you are so close to sound.
• White wire from new head goes to yellow wire in dash
• Grey wire on new head goes to blue wire in dash.
• Tape off ALL REMAINING WIRES FROM NEW HEAD, don't allow them to touch each other or any metal in the dash.
• This uses the factory fader, and factory amp, without messy rewiring.
• Anyone who tells you that the new radio has more watts than the old amp needs to look at what it takes to make 40x4 rms. It sure ain't gonna fit inside a deck, and it will need at least 10ga power wire, which new radios don't have.
• I worked the install bay many many years. I did every e30 like this, and my 88 535is has had this wiring for 6 years, no problems. There is a common thread on these boards that says 'rewire' when it is not needed.
• If you have the std system without an amp, it is just as easy, there are two extra wires. Email me for details if so.
• If you are confused, take it to a reputable shop ( no Best or Circuit in the name ). 40 bucks and you will be in and out in 10-15 minutes.

its 12am here and I'm tired and bored. The proper illumination wire found in the dash of e30's is Red/GREY not Red/grn as I said. So shoot me, lol.

Hey,thanks for the write-up. I know this is an old post but i'm hoping I could still get some help with my install. In bullet 4....I don't have a blue/wht or blue wire from my new head unit at all. I have a lot of extra wires too. Purples and grays...etc.

I think i need someone to write all the steps i need to take exactly as if I were the dumbest person ever (I'm not, i swear! lol). I have an 88' 325ic with the premium sound and in-dash fader. I bought a JVC KD-R870BT head unit. That's the only thing i plan on changing (the head unit), the rest I'm keeping....original speakers, amp and wiring. I've never done any sort of car electrical before so I'm a super novice. Any help would be greatly appreciated!

Thanks!

[jfallo]

Hi! I know this is an old thread but you might just be the person who can help me. I have a '90 325i cabrio. It already came with an aftermarket head unit when I bought it. I tried replacing the head unit and it was working fine until I pushed the new HU back in the dash. Suddenly no power. When I pulled it out to check the wiring, I noticed that the solid red wire got disconnect from the inside of the dash. Would you know where I should reconnect this red wire? It's still connected to the HU, but what I need to know is where in the car should the other end or that wire be connected to and what part/s of the dash I need to remove to access wherever I need to connect that red wire to. Thanks so much!!

- - - Updated - - -

If you have the premium system ( tweeter on doors, plate speakers on rear deck )

• Yellow wire from new head 12v+ goes to Red/grn in dash
• Red wire from head ign goes to purple/wht in dash
• Black wire goes to brown wire in dash plus two extra brn/blks that were attached to old head. There will be three wires total hooked to the black from new head.
• Blue/wht from new head goes to both white wires in dash. If you don't have a blue/wht on new head, use the blue.
• That will leave three wires:
• If your new head has a dimmer lead ( usually orange ) it will attach to the red/grn lead in dash. If the new head does not, TAPE THIS OFF. No sense blowing fuses now when you are so close to sound.
• White wire from new head goes to yellow wire in dash
• Grey wire on new head goes to blue wire in dash.
• Tape off ALL REMAINING WIRES FROM NEW HEAD, don't allow them to touch each other or any metal in the dash.
• This uses the factory fader, and factory amp, without messy rewiring.
• Anyone who tells you that the new radio has more watts than the old amp needs to look at what it takes to make 40x4 rms. It sure ain't gonna fit inside a deck, and it will need at least 10ga power wire, which new radios don't have.
• I worked the install bay many many years. I did every e30 like this, and my 88 535is has had this wiring for 6 years, no problems. There is a common thread on these boards that says 'rewire' when it is not needed.
• If you have the std system without an amp, it is just as easy, there are two extra wires. Email me for details if so.
• If you are confused, take it to a reputable shop ( no Best or Circuit in the name ). 40 bucks and you will be in and out in 10-15 minutes.

its 12am here and I'm tired and bored. The proper illumination wire found in the dash of e30's is Red/GREY not Red/grn as I said. So shoot me, lol.

Hi! I know this is an old thread but you might just be the person who can help me. I have a '90 325i cabrio. It already came with an aftermarket head unit when I bought it. I tried replacing the head unit and it was working fine until I pushed the new HU back in the dash. Suddenly no power. When I pulled it out to check the wiring, I noticed that the solid red wire got disconnect from the inside of the dash. Would you know where I should reconnect this red wire? It's still connected to the HU, but what I need to know is where in the car should the other end or that wire be connected to and what part/s of the dash I need to remove to access wherever I need to connect that red wire to. Thanks so much!!

[95BMWIC]

I was just thinking what ever happened to Snarcher!... ? 3800 posts in 2 years..

then BAM...gone.

like a candle in the wind...

And then I remembered seeing this...

https://www.bimmerforums.com/forum/s...-have-returned!

too funny.. epic radio post my friend

[afredo]

First of all, this thread does not completely apply to your situation. A '91 would have had a 4 channel factory head unit and not 2 channel with fader. Secondly, he makes a couple of choices which are non-optimal. Is your car equipped with a factory amp?

1. The above description is for the early premium system 2 channel head unit and external 4 channel amplifier. The original wiring for this arrangement used yellow (left) and blue (right) signal wires which are then split at the fader wheel into 4 signals (LF, LR, RF, RR) that run to the amplifier. Return is through chassis ground. These are the brown/black wires. (Original wiring in BMWs for this era use brown as a standard ground color.) Wiring the system in this way usually works, unless your head unit can't tolerate the common ground. This method makes the fader control in the new head unit non-functional. Instead it is still controlled via the fader control in the dash. Personally, I'd bypass the fader in this arrangement and connect all 4 signal wires to the corresponding wires post-fader. You'll leave the head unit speaker black stripe wires all unconnected. Instead the signal return path goes through chassis ground.

In this case the post-fader colors should be:
yellow/red (LF) connects to head unit white
yellow/black (LR) connects to head unit green
blue/red (RF) connects to head unit gray
blue/black (RR) connects to head unit purple

2. For the case with the later factory 4 channel system and factory amp where you still want to use the factory amp, you basically do this the same as bypassing the fader above.

3. If you choose to bypass the factory amp, you need to run all new pairs for the speakers and wire the speakers as specified by the head unit manufacturer.

4. Finally if you are wiring a car that did not have a factory amp, you'll have 4 twisted pairs that run to or near the head unit location. Sometimes you'll have to cut back the harness wrap a bit to find them. Each pair is a +/- set with the signal wire color as described above and the brown stripe wire the return ground. Wire the speakers as specified by the head unit manufacturer.

Hey guys, having issues installing an aftermarket deck in my 1990 325i coupe with premium sound. Late model so no fader in the dash. Factory amp I believe (there's a box behind the carpet on the driver side in the trunk behind the antenna actuator, assuming that's the amp?). Had the original deck, unmolested otherwise as far as I could tell, was owned by an old woman. Anyway, been trying to do this for hours now, finally stumbled across your long comment on the official e30 aftermarket radio install thread where you said the initial post didn't apply to late model premium sound cars. Here's what has happened so far:

Wired up new head unit to the four positive speaker wires in the car harness, and then wired up the negatives, as well as chassis ground, power and switched power, power antenna and amp turn on wires I wired together to the blue/white on the new deck harness. This caused only the passenger side rear speaker to play sound, and the deck's balance/fader controls did nothing, BUT the sound quality was excellent.

Then saw this comment, so I undid all the individual speaker grounds as you said it grounds thru the chassis ground, and doing this got sound to come out of all 4 speakers. Unfortunately now for whatever reason, when the amp powers on and the rear speakers kick on, they sound like absolute ass.

What am I doing wrong?! Clearly the rear speakers aren't blown because the one single rear speaker that worked when I had all the speaker grounds connected in addition to the chassis ground sounded great.

I guess what I'm trying to find out is, how do I wire this so all speakers work, the deck's fader/balance controls work, and the rear speakers don't sound like shit when the amp comes on?