Understanding E30 speaker and amp wiring

[SPOautos]

Do you happen to know if you have the "premium sound" with tweeters in the doors? This is the easiest indication of whether the car came with the amp or not. Depending on what power output the Kenwood stereo has, it's likely that bypassing the factory amp is your best bet. The process is fairly simple as long as you're comfortable cutting into the stock harness. It is a bit destructive and, depending on how cleanly you do it, can or can't be easily put back to stock at a later time.

At the amp, you just need to identify input wires (one per channel, they share a ground) and tie them to their corresponding output wire (plus add ground wires since stock output uses two wires). The speaker wire in the later models include +ve and -ve and are decent enough for a basic system. If you'd rather replace the amp altogether, that's likely to be even more work as you're not going to find something that uses the factory plug and you'll have to work out how to get signal to it, along with power.

On my build I just added RCA down the center console, out to the trunk, and am leaving the speaker signal disconnected at the head unit. I'm replacing the factory amp in my car with an aftermarket and reusing the existing twisted pair speaker wires for simplicity.

Lastly, if you find that the speakers need replacing (and you have tweeters) keep in mind that the passive crossovers were built in to the 5.25" speakers so you'll want to take that into consideration when purchasing replacements.

Yes, it's the premium sound....well, it has the trunk amp and separate tweeters so I suppose that's premium sound.

Do you know if anyone has ever made jumper wires at the amp to go between the input/outputs? If it the connectors have to be cut off in order to bypass, then I think rather than cutting them, I might buy a 4 channel amp and run RCA's from the head unit. That way I can leave the factory wiring alone. Do you happen to know what gauge power wire and size fuse is powering the factory amp? Could I use the factory power wire for a 4x75rms amp or something like that?

When you were talking about the passive crossovers being built in to the fronts, I don't think I'm following. Are you just saying to make sure I get speakers that come with a crossover?

Thanks for your help!!!

[BSAmarc]

Do you know if anyone has ever made jumper wires at the amp to go between the input/outputs? If it the connectors have to be cut off in order to bypass, then I think rather than cutting them, I might buy a 4 channel amp and run RCA's from the head unit. That way I can leave the factory wiring alone.

I would reach out to bradnic@oemhifi.com to see if he has anything.

Do you happen to know what gauge power wire and size fuse is powering the factory amp? Could I use the factory power wire for a 4x75rms amp or something like that?

30A fuse, 14 gauge wire. Since _all_ wires in and out of the factory amp go through that single that connector, you'd need to hack up the connector to get to them anyways. Better to wire up a new amp using new cabling. Since coupes and sedans have the battery in the trunk, there is an unused channel on the passenger (right) side of the car running all the way to the trunk that you can use for your cabling.

When you were talking about the passive crossovers being built in to the fronts, I don't think I'm following. Are you just saying to make sure I get speakers that come with a crossover?

Correct. Don't just pick up 5.25" speakers expecting there to be a separate crossover behind the panels. Either buy a component sets or a separate crossover.

[SPOautos]

I would reach out to bradnic@oemhifi.com to see if he has anything.


30A fuse, 14 gauge wire. Since _all_ wires in and out of the factory amp go through that single that connector, you'd need to hack up the connector to get to them anyways. Better to wire up a new amp using new cabling. Since coupes and sedans have the battery in the trunk, there is an unused channel on the passenger (right) side of the car running all the way to the trunk that you can use for your cabling.


Correct. Don't just pick up 5.25" speakers expecting there to be a separate crossover behind the panels. Either buy a component sets or a separate crossover.

Thanks for the info! Okay so I can just leave the input connector alone, run a 8 gauge power wire, two sets of rca's, and auxiliary wire, down the passenger side and I guess they snake through the convertible top compartment and into the trunk. I suppose for the speaker wires I'll have to either cut the connector off or depin it.

What do you think is the best way to mount the amp in order to use the factory speaker wires? Just somehow attach it to that back wall where the original amp is? Id like to do it without drilling any holes, but not sure if that'll be possible or not.

[BSAmarc]

I don't know what the trunk space looks like in a convertible, but I'm looking to mount mine to the rear of the back seat, on a board that sits behind the cardboard panel. So the install will be:

steel back seat | wooden board | cardboard panel | amp

This way I can size the board to match existing holes and bolt the amp solidly to it.

[bradnic]

Yes, it's the premium sound....well, it has the trunk amp and separate tweeters so I suppose that's premium sound.

Do you know if anyone has ever made jumper wires at the amp to go between the input/outputs? If it the connectors have to be cut off in order to bypass, then I think rather than cutting them, I might buy a 4 channel amp and run RCA's from the head unit. That way I can leave the factory wiring alone. Do you happen to know what gauge power wire and size fuse is powering the factory amp? Could I use the factory power wire for a 4x75rms amp or something like that?

When you were talking about the passive crossovers being built in to the fronts, I don't think I'm following. Are you just saying to make sure I get speakers that come with a crossover?

Thanks for your help!!!

Sorry I missed this. Check out my no-cut sound system bypass harnesses at oemhifi.com

https://oemhifi.com/products/quadroboost-trunk-amp-bypass-harness

[reggieb]

...snipped all the great info...

I am trying to figure out the wiring in my car. It's a 1993 convertible (the convertible in 1993 was still an e30) and I can't quite get it.

All of the POWER side stuff matches up with what is in this thread: https://www.r3vlimited.com/board/for...and-amp-bypass

I have that connected up and my new head unit powers on.

I do have an amp in the truck, and ordered the bypass only from you guys. Which I will hook up. I wanted to temporarily, while I wait for that, just check that everything is working. My speaker wires don't match up with that thread. I am using the solid yellow and solid blue wires for the front positive, it's possible that is wrong and I should go up above wherever they're spliced, but I am using them where they come in to my 2 - 4 channel adapter, which has the same connectors as the one that you have a picture of, but different wiring (when contrasting to this: https://oemhifi.com/products/oem-2-to-4-channel-premium-sound-adapter-harness?pr_prod_strat=e5_desc&pr_rec_id=15d62ac7e& pr_rec_pid=8744351727889&pr_ref_pid=9054229954833& pr_seq=uniform)

My negative wires are definitely all different colors than the diagram for the convertible in your OP, and at the wiring link from the other thread.

Here is what I have:



All of my messing around, I never got any sound out of the system. I did try grounding the pair of brown wires that were grounded to the back of the old stereo and that didn't help either.

Here are all of the colors that I am hooked in to for the positives:
Solid Blue (Right Front)
Solid Yellow (Left Front)
Blue/Black (Right Rear)
Yellow/Black (Left Rear)

Yellow Red (this is also left right?)
Blue/Red (Also right front?)

Grey/Red (This is in the diagram, but shows as being between the speaker and the amp, and shouldn't be wired to the stereo, but I have it running to that connector pictured)
Brown/Black (Again, this is a color I understand to be running as a NEGATIVE to one of the speakers from the amp, but is wired in behind my stereo)

I can't get any sounds out of the speakers from what I have going on here. Do I need to splice in higher up the chain to get to the colors described in that post?



I took pause I I thought it is possible that since I have a car that overlaps with the e36, the parts bin sharing might have changed a bit. I am also replacing a BMW stereo, but not the one that the car started life with I don't think. So that might be the source of the different wiring. Would I see different colors north of that Y split?

[bradnic]

I am trying to figure out the wiring in my car. It's a 1993 convertible (the convertible in 1993 was still an e30) and I can't quite get it.

You have 4 channel premium sound wiring. It uses a single wire for each radio channel output, and a single signal ground wire to the amp in your trunk. The wiring to the speakers comes from the trunk amp, not the radio. Colors are different from the radio output wiring as well. Take a look at the 1st post on this thread for a full description of your setup, including the wire colors for radio outputs, speakers, power, chassis and ground.

All of the POWER side stuff matches up with what is in this thread: https://www.r3vlimited.com/board/for...and-amp-bypass
I have that connected up and my new head unit powers on.

From the pics you posted, it's clear your illumination and memory wiring has been cut. You'll need to repair that to run a factory radio.

I do have an amp in the truck, and ordered the bypass only from you guys. Which I will hook up.

Already shipped out. The adapter connects the radio output wires to the amp output wires through the trunk amp connector. letting you run a radio only setup. Please note the radio you use must be compatible with 'single-ended' shared signal ground wiring.

I wanted to temporarily, while I wait for that, just check that everything is working. My speaker wires don't match up with that thread.

The factory speaker wires in a premium setup DO NOT go to the radio. There are 4 grey wires for the front channels, 4 black wires for the rear.

I am using the solid yellow and solid blue wires for the front positive, it's possible that is wrong and I should go up above wherever they're spliced, but I am using them where they come in to my 2 - 4 channel adapter, which has the same connectors as the one that you have a picture of, but different wiring (when contrasting to this: https://oemhifi.com/products/oem-2-to-4-channel-premium-sound-adapter-harness?pr_prod_strat=e5_desc&pr_rec_id=15d62ac7e& pr_rec_pid=8744351727889&pr_ref_pid=9054229954833& pr_seq=uniform)

The 2-4 channel adapter has a two black striped wires for the rear radio outputs, one yellow and one blue. The solid yellow and solid blue wires are your radio front outputs. All 4of these wires are "positive".

My negative wires are definitely all different colors than the diagram for the convertible in your OP, and at the wiring link from the other thread.

This seems to contradict what you write later on. Maybe you're talking about the grey and black speaker wires?

Here is what I have:
[/QUOTE]
That's the OEM rear channel adapter for the radio outputs. Same one you linked to on my site. The part you are holding plugs into a fader connector on your wiring harness.

All of my messing around, I never got any sound out of the system. I did try grounding the pair of brown wires that were grounded to the back of the old stereo and that didn't help either.

Those two brown wires are "case ground" for the radio, and signal ground for the radio outputs. You will need your trunk amp plugged in, and *must* connect that case ground to get undistorted audio.

Here are all of the colors that I am hooked in to for the positives:
Solid Blue (Right Front)
Solid Yellow (Left Front)
Blue/Black (Right Rear)
Yellow/Black (Left Rear)

Those are all correct.

Yellow Red (this is also left right?)
Blue/Red (Also right front?)

You don't need to connect those to anything. Just plug the fader connector in.

Grey/Red (This is in the diagram, but shows as being between the speaker and the amp, and shouldn't be wired to the stereo, but I have it running to that connector pictured)

The grey/red wire in the radio opening is NOT for speakers.

Brown/Black (Again, this is a color I understand to be running as a NEGATIVE to one of the speakers from the amp, but is wired in behind my stereo)

The only brown/black wire going directly to your radio should be on the power connector. There's another brown/black wire buried in the harness that goes between to the trunk amp

I can't get any sounds out of the speakers from what I have going on here. Do I need to splice in higher up the chain to get to the colors described in that post?

I strongly recommend you restore your wiring to stock - don't cut it.

I took pause I I thought it is possible that since I have a car that overlaps with the e36, the parts bin sharing might have changed a bit. I am also replacing a BMW stereo, but not the one that the car started life with I don't think. So that might be the source of the different wiring. Would I see different colors north of that Y split?

Drop me a note and we can chat further. Can't really tell what's going on with your harness in that pic. I suspect your radio wiring has been cut all the way back to the fader connector.

[reggieb]

You have 4 channel premium sound wiring. It uses a single wire for each radio channel output, and a single signal ground wire to the amp in your trunk. The wiring to the speakers comes from the trunk amp, not the radio. Colors are different from the radio output wiring as well. Take a look at the 1st post on this thread for a full description of your setup, including the wire colors for radio outputs, speakers, power, chassis and ground.

I did indeed read through (and printed it) but it doesn't quite match up, which is where my confusion came in

From the pics you posted, it's clear your illumination and memory wiring has been cut. You'll need to repair that to run a factory radio.

I am not interested in running a factory radio, so that isn't an issue. I have it wired to the harness on my Blaupunkt now.

Those two brown wires are "case ground" for the radio, and signal ground for the radio outputs. You will need your trunk amp plugged in, and *must* connect that case ground to get undistorted audio.

Cool, so I can just connect them in with the Brown/Black that I have connected to the ground wire out of the back of the stereo? Or do I need to actually find a ground point to connect them to?

You don't need to connect those to anything. Just plug the fader connector in.


The grey/red wire in the radio opening is NOT for speakers.

Got it, I'll cap them.

The only brown/black wire going directly to your radio should be on the power connector. There's another brown/black wire buried in the harness that goes between to the trunk amp

There was one running right in to the connector that you describe as the "Rear channel adapter" that I linked on your site. Like I said, while the adapter itself is the same physical plug, the wiring both in and out of it don't match what's on your site - that's the biggest source of pause for me.

I strongly recommend you restore your wiring to stock - don't cut it.

Man, I would have loved to not cut it, but I don't like taps, and I don't really think there is a better way to wire in an aftermarket radio. If someone made me a wiring harness, I would have gladly used it, like I have in other cars I've wired, but I couldn't find one. I cut the absolute minimum that I could, then used WAGO connectors. I still have the connectors that I cut off. I could reconnect them and lose around 1cm of length, but don't really think that's necessary. I think we'll drive this car in to the ground with an aftermarket radio in it.

Drop me a note and we can chat further. Can't really tell what's going on with your harness in that pic. I suspect your radio wiring has been cut all the way back to the fader connector.

Cool, and I did email you. Since I think I have the positives right, and I don't have any of the negatives from the wiring threads, I guess I just need to know what to connect those to. I assume that once I have the bypass in place, I will have to have a negative wired from the stereo, else the speakers won't work. Since I don't have the colors of wires described in that other threads for the negatives, what do I do? Or is it that once I have that bypass in place I just won't need anything connected to those? That just feels very wrong to me.

EDIT: From further reading, I guess I just don't connect the negatives? So why would there have been no sound? Perhaps just a dead amp that will be resolved when I get your bypass?

EDIT 2: I think that my stereo isn't going to like common ground and I should just run new speaker wire.

[B2NTY]

Yo, I'm doing a sound system conversion on my early model. I know my way around e30s but I'm a complete rookie when it comes to wiring and audio. It came with a non-premium system and I'm upgrading it to a late-model premium system with a cm5908. I currently have the late-model rear speakers and tweeters, the front tweeters, and the Blaupunkt amp. I need to get a hold of the front footwell speakers to figure out the wiring. I've been looking for the OEM wiring harness I need (which I believe is 61-12-1-381-719). However, when I found a guy doing a part out with the late-model premium system and talked to him he highly recommended doing aftermarket wiring instead. Everything in the setup would be OEM late model premium and I wouldn't mind having the OEM harness but I'm also open to doing aftermarket wiring because I think it would be a fun thing to do (I'm aware that it is a difficult thing and can be a pain but I like that stuff :) ). I plan on using cassette tapes and making my own mixes using a cassette deck to record them on, so I want to have full OEM functionality. What should I do? Just go with my plan of getting the OEM harness which the guy I talked to about this stated " The sound quality is extremely poor" when referring to the OEM wiring or do I go aftermarket wiring?

A follow-up to this is understanding 2-channel vs. 4-channel. What is the difference and how do these types of wiring affect what I'm trying to do?

[bradnic]

Yo, I'm doing a sound system conversion on my early model.

I know my way around e30s but I'm a complete rookie when it comes to wiring and audio. It came with a non-premium system and I'm upgrading it to a late-model premium system with a cm5908

Welcome to R3V! I have an 86 325 that I'm doing the same thing to. If you haven't already done so, get your radio and amp rebuilt. The amps have a 100% failure rate in my experience, even if they haven't been used. 30+ year old radios also need rebuilds and tape maintenance if you plan to keep that.

I currently have the late-model rear speakers and tweeters, the front tweeters, and the Blaupunkt amp. I need to get a hold of the front footwell speakers to figure out the wiring. I've been looking for the OEM wiring harness I need (which I believe is 61-12-1-381-719. However, when I found a guy doing a part out with the late-model premium system and talked to him he highly recommended doing aftermarket wiring instead.

YOU DON'T NEED AFTERMARKET WIRING UNLESS YOU'RE RUNNING A SUB OR EXTREMELY HIGH POWER LEVELS
Unfortunately there are literally hundreds, maybe even low thousands of E30s out there with butchered audio wiring. These cars are all classics now, so continuing that practice is certainly not a good idea. When it comes to stock audio wiring, I personally let basic electrical engineering and "OEM+" guide my thinking. You also need to be clear on what your audio goals are, but I can say flat out that there is absolutely NO engineering driven reason to cut the factory audio wiring, PERIOD. I do know folks that just won't accept that statement, but I stand by it.

Those that insist on aftermarket wiring often have the idea that you need very heavy gauge wiring to run power to the speakers. Unless you're running over 150 watts to EACH CORNER of the car, it's just not true, and even then, the only physical effect from running that much power through the wires is a slight temperature rise, maybe 1-3 degrees. Note I DID NOT include power wiring in this discussion. That's a completely different conversation, especially if you intend to run a trunk sub or high powered radio of some sort (like a 5908 with Amp+ in an install that uses the speaker output wires). But there's no stock sub wiring anyway, so it's a moot point.

RETROFITTING LATE MODEL PREMIUM WIRING
Retrofitting the late model twisted pair premium / sound system harnesses is the right direction for an OEM+ build on an early model car (719 for coupe/sedan, 718 for convertible). There are 2 reasons you only want the twisted pair version of these harnesses:

1) noise reduction from the twister pair setup (basically it's just as effective as a coax cable)
2) better power handling with slightly thicker gauge wiring on the speaker outputs.

Note: I confirmed with BMW Classic a while ago now that while both the radio only and premium audio wiring was modified to twisted pair radio outputs and speaker outputs some time in 89, the part number did not change. You don't want to use the earlier 718 and 719 wiring if you can avoid it, because it's not twisted pair, and it uses a 5 wire radio output setup, not 8.

LIMITATIONS OF LATE MODEL PREMIUM WIRING
Even with a late model premium harness though, there are two major limitations which require "no-cut" workarounds, both of which are solved without cutting anything:
1) the radio outputs have 'single ended', common ground wiring at the radio and amplifier ends of the harness. This is by far the biggest hassle to deal with on factory sound system wiring, as some aftermarket radios / radio upgrades require individual radio output grounds to work properly.

The workaround for this is either
(a) don't use the radio output wiring - instead use a radio with pre-outs or a harness adapter kit like the one I created for Amp+
(b) stick to stock radios or aftermarket radios that are confirmed to work properly with common ground radio outputs.

2) there is no direct connection between the radio and the speakers. So unless your sound system equipment is 100% stock you will need to use by-pass harnesses in the trunk. Again, this is a completely solved problem.

Everything in the setup would be OEM late model premium and I wouldn't mind having the OEM harness but I'm also open to doing aftermarket wiring because I think it would be a fun thing to do (I'm aware that it is a difficult thing and can be a pain but I like that stuff :) )

I do get that, really. But you can still scratch that itch and leave your wiring stock though the bypass harnesses and trunk sub wiring.

I plan on using cassette tapes and making my own mixes using a cassette deck to record them on, so I want to have full OEM functionality. What should I do? Just go with my plan of getting the OEM harness which the guy I talked to about this stated " The sound quality is extremely poor" when referring to the OEM wiring or do I go aftermarket wiring?

It is flat out NOT TRUE that the twisted pair premium stock wiring limits audio quality. The greatest limitation to OEM audio quality in these cars has always been SIGNAL SOURCE, followed by THD from the radio's internal amp and trunk amp (if you're running at high volume levels). So unfortunately this includes tapes. I totally get the absolutely legit emotional appeal of tapes (and vinyl), but even if you record with a 3 head azimuth adjusting tape deck like a Nakamichi 680ZX or a Dragon, your tape recordings will never sound as good as a high quality BT solution. It will definitely sound better recorded on a 3 head deck though.

A follow-up to this is understanding 2-channel vs. 4-channel. What is the difference and how do these types of wiring affect what I'm trying to do?

2 channel vs 4 channel refers to the radio output wires in the audio harness (all audio harnesses have 4 channels to the speakers). 2 channel radios required a fader to distribute the radio outputs to all 4 corners of the car. The fader wiring has 4 radio output positive wires going to the amp (premium) or speakers (radio only), and 2 output positives to the radio itself. 4 channel premium wiring still has that fader connector as well, but it adds an adapter for the rear channel positives.

[B2NTY]

Welcome to R3V!

Thank you! I've been a lurker on the forums for a while but I'm happy to be a participating member.

If you haven't already done so, get your radio and amp rebuilt. The amps have a 100% failure rate in my experience, even if they haven't been used. 30+ year old radios also need rebuilds and tape maintenance if you plan to keep that.

I think I'd be happy to try and take on the rebuild of them. I've built computers and worked with soldering quite a bit when I was a kid. Would you happen to know anywhere I could find some instructions on rebuilds for the amp and cm5908 and also parts for it?

YOU DON'T NEED AFTERMARKET WIRING UNLESS YOU'RE RUNNING A SUB OR EXTREMELY HIGH POWER LEVELS
Unfortunately there are literally hundreds, maybe even low thousands of E30s out there with butchered audio wiring. These cars are all classics now, so continuing that practice is certainly not a good idea. When it comes to stock audio wiring, I personally let basic electrical engineering and "OEM+" guide my thinking. You also need to be clear on what your audio goals are, but I can say flat out that there is absolutely NO engineering driven reason to cut the factory audio wiring, PERIOD. I do know folks that just won't accept that statement, but I stand by it.

Those that insist on aftermarket wiring often have the idea that you need very heavy gauge wiring to run power to the speakers. Unless you're running over 150 watts to EACH CORNER of the car, it's just not true, and even then, the only physical effect from running that much power through the wires is a slight temperature rise, maybe 1-3 degrees. Note I DID NOT include power wiring in this discussion. That's a completely different conversation, especially if you intend to run a trunk sub or high powered radio of some sort (like a 5908 with Amp+ in an install that uses the speaker output wires). But there's no stock sub wiring anyway, so it's a moot point.

I agree, it's unfortunate the amount of harnesses are butchered (including mine due to the PO), it makes it feel impossible to find an uncut one. MY GOAL IS CLEAR, I WANT TO HEAR MUSIC COMING OUT OF THE SPEAKERS AND INTO MY EARS. I'm in no way an audiophile and currently use an almost decade-old portable speaker for music in my car ATM and am fine with using even just my phone speaker.

Note: I confirmed with BMW Classic a while ago now that while both the radio only and premium audio wiring was modified to twisted pair radio outputs and speaker outputs some time in 89, the part number did not change. You don't want to use the earlier 718 and 719 wiring if you can avoid it, because it's not twisted pair, and it uses a 5 wire radio output setup, not 8.

So I should not be using the 719 for my early model coupe? What harness should I be looking for then?

LIMITATIONS OF LATE MODEL PREMIUM WIRING
Even with a late model premium harness though, there are two major limitations which require "no-cut" workarounds, both of which are solved without cutting anything:
1) the radio outputs have 'single ended', common ground wiring at the radio and amplifier ends of the harness. This is by far the biggest hassle to deal with on factory sound system wiring, as some aftermarket radios / radio upgrades require individual radio output grounds to work properly.

The workaround for this is either
(a) don't use the radio output wiring - instead use a radio with pre-outs or a harness adapter kit like the one I created for Amp+
(b) stick to stock radios or aftermarket radios that are confirmed to work properly with common ground radio outputs.

2) there is no direct connection between the radio and the speakers. So unless your sound system equipment is 100% stock you will need to use by-pass harnesses in the trunk. Again, this is a completely solved problem.

I'm going all OEM here, speakers, amp, cm5908, and I'm thinking harness now but am going to keep these in mind.

I do get that, really. But you can still scratch that itch and leave your wiring stock though the bypass harnesses and trunk sub wiring.

Yeah I keep my hands full with the itch lol. I've done a five lug swap and after I handle this I'm going to be getting ready for a 13B turbo swap. It's gonna be really painful but really fun. :,)

It is flat out NOT TRUE that the twisted pair premium stock wiring limits audio quality. The greatest limitation to OEM audio quality in these cars has always been SIGNAL SOURCE, followed by THD from the radio's internal amp and trunk amp (if you're running at high volume levels). So unfortunately this includes tapes. I totally get the absolutely legit emotional appeal of tapes (and vinyl), but even if you record with a 3 head azimuth adjusting tape deck like a Nakamichi 680ZX or a Dragon, your tape recordings will never sound as good as a high quality BT solution. It will definitely sound better recorded on a 3 head deck though.

Yeah, I'm aware I'm gonna be losing out on quality but that doesn't bother me at all. As I said earlier, I'm not an audiophile. I simply just want to hear the music and use the OEM system. I was born in the early 2ks so using older stuff like this is interesting and fun for me because it was never a norm throughout my life. I'll be using a 3 head deck for recording tapes but will also be using tapes of albums made by artists.

Thank you so much for all the info! I think I'll be going with the premium wiring harness route and sourcing one from a part out. I'll most likely be getting the OEM wiring to repair kit from Cantelope radio or OEM HIFI (which I believe is you) because I'm sure wherever I get it from it'll be gutted at the head unit. So I'm going the OEM late model premium wiring harness route and will be having a pure OEM system with a rebuild of the amp and head unit. Is there anything else I should know for/about this swap?

[bradnic]

So I should not be using the 719 for my early model coupe? What harness should I be looking for then?

as I wrote earlier, you want the twisted pair version of the 719 harness for a coupe or sedan.

Yeah, I'm aware I'm gonna be losing out on quality but that doesn't bother me at all. As I said earlier, I'm not an audiophile. I simply just want to hear the music and use the OEM system. I was born in the early 2ks so using older stuff like this is interesting and fun for me because it was never a norm throughout my life. I'll be using a 3 head deck for recording tapes but will also be using tapes of albums made by artists.

love it!

[strickland]

Hello!

First of all, bradnic you rock! I am also a diy’er who knows his way around the E30, but I’m a total rookie in regards to audio. Glad to gave found a specialist. My setup & questions follow…

I have an 89 coupe with premium sound. I assume it’s the 4 channel late model. (How do I confirm this?)

I’m thinking about replacing the oem amp with your refurbished amp. Then I can keep my oem wiring in the trunk, correct? Just plug & play? No need to replace that pigtail?

I’m also wondering if I could / should add a small active sub to the stock setup? I found a simple RCA line output converter, but not sure where to connect it. Is it better to splice in the RCA from the headunit side, or the trunk amp?

I have an older aftermarket headunit with pigtail (no rca out). Not OEM but I would like to keep the headunit. Should that be rebuilt too?

Thanks in advance!!!

[bradnic]

Hello!

First of all, bradnic you rock! I am also a diy’er who knows his way around the E30, but I’m a total rookie in regards to audio. Glad to gave found a specialist. My setup & questions follow…

glad you found the info helpful! Lots of work went into this. Some brief answers below, but please reach out via bradnic@oemhifi.com to discuss things in depth.

I have an 89 coupe with premium sound. I assume it’s the 4 channel late model. (How do I confirm this?)

depends on your car’s build date. BMW cut over to 4 channel wiring in late 89. If you have a fader below your center ac vents then you most likely have the 2 channel non-twisted pair wiring with a single shared radio output ground.

I’m thinking about replacing the oem amp with your refurbished amp. Then I can keep my oem wiring in the trunk, correct? Just plug & play? No need to replace that pigtail?

completely plug and play, as are all my wiring products. Respect the OEM design - NEVER cut your factory wiring!

I’m also wondering if I could / should add a small active sub to the stock setup? I found a simple RCA line output converter, but not sure where to connect it. Is it better to splice in the RCA from the headunit side, or the trunk amp?

super easy to do this with a Sound System setup. I have adapter harness options for sub setups as well. If you use a small powered sub like the Alpine PWE-S8 I have adapters that allow you to power it right from the trunk amp connector, no wire cutting.

I have an older aftermarket headunit with pigtail (no rca out). Not OEM but I would like to keep the headunit. Should that be rebuilt too?

drop me an email and we can discuss

[strickland]

Thanks so much! I will email you for more detail.

yes I have the fader wheel under the air vents. It seems to create a lot of static. I’ve tried replacing it with a bunch of used fader knobs but the result is still static-y. I’d like to delete it.