Radio Wiring and Amp Bypass

[StereoInstaller1]

Yes, exactly. It's best if you test from the trunk, but you would need to unplug the deck.

[Excellent30]

Hello everyone, I have a 1988 325i Convertible with tweeters and a stock amp in the back. After installing a new head unit, the sound does not work past a certain (medium) volume due to the amp. I purchased a cheap 4 channel amp to replace the stock one instead of running new wires all around. When I cut the amp harness in the back, I noticed that there was only 16 wires. I do not know which ones belong to which speaker because this assortment of colors does not match any guides I have read. They are:

One that's all white (power?)
One that's all brown (ground?)
Black/White
3x Black/Brown
Grey/White
Grey/Brown
Red/Grey
Red/White
Yellow/Red
Yellow/Black
Blue/Black
Blue/Brown
Violet/Grey
Violet/Black

Any help is highly appreciated, I have been trying to figure this out for a while.
Thank you

[Bullhead]

This may have been said , but do you use the crimp splices or do you actually cut into the dash wires to connect to the aftermarket deck? Or does it not matter?

[Bullhead]

Hey Luke I have an 87 just has 4 speakers and no fader. I only see 2 sets of speaker wires and when I test them they just power the fronts. I looked behind the antenna and all I found was the lighting box so I don't think I have an amp either. Are the speaker wires for the back and front under the rear seat? And should I just run some monster wire to the rears, I would like to use the stock setup but I am confused.

[325Eblue]

Alright so I made it thru 15 pages of this monster 30 page thread pretty sure I got a handle on what needs to get done. I however what some advice before going any further , he he the reward is a super clean pic of the inside of a 27 year old stock amp blaupunkt I think these are and it looks like it should be working? idnk , there are no burn marks,no swollen capacitors, nothing melted etc just gave up I guess? SO thanks to a super kewl RV3 dude I have another stock amp coming in the mail and that should be a good temporary band aid while I sort out the next step, just couldnt go without music on the morning drive anymore and I really dont wnat to hear the brake limiter noises telling me to work on that gees whats more important here LOL

the ride is a 1987 325 is she has the front tweeter pods, has a working fader, had a working trunk amp, the PO installed a JVC head unit the rear speakers are orginal the rectangle shape with the raised angled seperated horn. Okay so the JVC head unit was playing clean and loudly with the stock premium system, working fader amp etc. The amp has died I am pretty sure the front tweeter pods were still working because the music was pretty loud, umm cant remember what is in the kick panel under the front dash, hope I am not missing anything for a good diagnosis Paging DR. Luke

So it seems like with an aftermarket head unit already installed, speaker sound good, fader working, and most everything at hand in good shape I have an easier task but here is my question... sorry in advance for this thread clogging size post

looking at the back of the stock amp you can see a group of 4 wires together then a single solo wire , then a group of three wires.... after that it repeats the same grouping in reverse so then a group of 3 wires , then a single solo wire, then a group of 4 wires so 8 per pattern X's 2 patterns 16 total.

Couldnt I find a way to just de-solder these leads and re-solder to a modern input plug to mate to a modern amp producing channels back in the loop to the stock harness and speakers?

I would be upgrading the amp but keeping the circuit in the same closed loop pattern?

Thanks much :grin: S

[StereoInstaller1]

Alright so I made it thru 15 pages of this monster 30 page thread pretty sure I got a handle on what needs to get done. I however what some advice before going any further , he he the reward is a super clean pic of the inside of a 27 year old stock amp blaupunkt I think these are and it looks like it should be working? idnk , there are no burn marks,no swollen capacitors, nothing melted etc just gave up I guess? SO thanks to a super kewl RV3 dude I have another stock amp coming in the mail and that should be a good temporary band aid while I sort out the next step, just couldnt go without music on the morning drive anymore and I really dont wnat to hear the brake limiter noises telling me to work on that gees whats more important here LOL

the ride is a 1987 325 is she has the front tweeter pods, has a working fader, had a working trunk amp, the PO installed a JVC head unit the rear speakers are orginal the rectangle shape with the raised angled seperated horn. Okay so the JVC head unit was playing clean and loudly with the stock premium system, working fader amp etc. The amp has died I am pretty sure the front tweeter pods were still working because the music was pretty loud, umm cant remember what is in the kick panel under the front dash, hope I am not missing anything for a good diagnosis Paging DR. Luke

So it seems like with an aftermarket head unit already installed, speaker sound good, fader working, and most everything at hand in good shape I have an easier task but here is my question... sorry in advance for this thread clogging size post

looking at the back of the stock amp you can see a group of 4 wires together then a single solo wire , then a group of three wires.... after that it repeats the same grouping in reverse so then a group of 3 wires , then a single solo wire, then a group of 4 wires so 8 per pattern X's 2 patterns 16 total.

Couldnt I find a way to just de-solder these leads and re-solder to a modern input plug to mate to a modern amp producing channels back in the loop to the stock harness and speakers?

I would be upgrading the amp but keeping the circuit in the same closed loop pattern?

Thanks much :grin: S

So, I don't understand why you would care if that stock amp plug gets cut off or not, seems a damn silly thing to worry about, especially since someone hacked the front to put a JVC in.

You could unsolder the plug and solder wires on...or just crimp little pins on those same wires and plug each one in. I guess if you have a spare amp lying around, but sure seems like a buttload of hassle for nothing.

Oh BTW: using speaker level signal for an amplifier input is pure hack when you have an aftermarket deck and an aftermarket amp. Get off your ass and run some fucking RCAs. (exception: if you own one of those Alpine KTP445, use high level because you bought a shitball amplifier) Use that stock harness (seriously, why would you care if it's hacked? Resale?) for speaker wires, but to use it with an aftermarket deck as an amp input is just horrid. (again, unless you bought that turd of an Alpine)

As far as that stock plug pinout sequence, its not that complex. You have 4 positive inputs, 2 negative signal grounds (chassis ground on all BMWs BTW) 4 pairs of speaker wires, power, ground and remote. It's nothing unusual, just 4 pairs of speaker wires with inputs and power, like any other little POS stock amp in pretty much any car so equipped.

[325Eblue]

Alright yes I do have a spare amp so I wanted to keep the plug intact but the thought was just to leave everything intact and just plug in a new better amp same location same wiring set up just different amp thought instead of hacking into the rear harness bundle just plug in the adapter and use the desolder leads to go into the new amp not changing anything but the amp thanks again for getting back to me I may be inheriting a 528i wagon touring lots of room for some killer new audio gear that you have seemed to perfected for beemers thanks brutha!

[brbahner]

Hey so i know you audio gurus will think this is a ridiculous question, but fuse 23 has been blowing on me and im assuming its because of my aftermarket head unit and the way its wired. i would like to pull it and use a delete panel while i try and figure out what to do about audio in the near future. So my question is, do i just cap all the wires when i get behind the unit? or is there a specific way to delete a head unit and connect the wires while keeping their integrity for a later date. i have premium sound if thats of any help.

[StereoInstaller1]

Hey so i know you audio gurus will think this is a ridiculous question, but fuse 23 has been blowing on me and im assuming its because of my aftermarket head unit and the way its wired. i would like to pull it and use a delete panel while i try and figure out what to do about audio in the near future. So my question is, do i just cap all the wires when i get behind the unit? or is there a specific way to delete a head unit and connect the wires while keeping their integrity for a later date. i have premium sound if thats of any help.

A simple question...ya, just tape off the wires, it's only 12 volts

[Bullhead]

I found the fader, but it only has 6 wires coming from it. So I guess I have to run new speaker wires IIRC the other stuff. Oh well.

[StereoInstaller1]

I found the fader, but it only has 6 wires coming from it. So I guess I have to run new speaker wires IIRC the other stuff. Oh well.

So that means you have an early car and that you didn't read the whole thread... Can't say I blame you, it's HUGE.

Here's the basics: either run new wire to the fronts or run 2 pair to the amp.

Either way, you can use the 4 existing wires to run the rear speakers, so those are already at the stock amp plug.

Good luck, if you get stuck let me know.

Go kick it's ass!

Luke

[Bullhead]

Bro I can't find an amp for sheite, and my car just has 4 speakers and no tweeters.

[fuzzysux]

vert premium radio

hey Luke,
thank you very much for posting the wire colors and info on amp etc.. i have just finished a complete reworking of my factory premium system with fader on an 88 vert. figured i'd provide some small insight for others and perhaps you can add this info where appropriate in the first few pages (since it can be very hard to find in the 30 page thread).

factory fader - as you said.. does not have enough wires inputs.. my car came with a horribly installed kenwood using only 2 channels which were split then amped.. it sounded aweful!. there is no reason for this fader.. if you are replacing your radio with aftermarket, the radio will have this feature.
64111368498 this is the part # for the appropriate plug to fill in the hole after you throw your fader directly in the garbage.

BEYOND FADER WIRING - Premium stereo - early car.
the factory harness here is pretty long, so you can cut out the fader (all corresponding wires to/from).
on the premium stereo for early cars, you will now be left with only found 4 input wires, yellow/red yellow/black blue/red blue/black and two brown/black. this means there is an amplifier. in the convertible, it is not near the antenna - it is on the back wall on the left.
-pull out trunk felt after removing the 8 or so small black clips
-unplug harness
-clip 2 or 3 wire ties and the end of this harness should not be at about your spare tire making it much easier to work on than climbing into your trunk.

now, for those who might be confused about using the stock wiring to run your rear speakers:

i connected my deck as follows for rear output:
yellow/red wire for left rear positive
yellow/black wire for left rear negative
blue/red wire for right rear positive
blue/black wire for left rear negative

for this to work, you have to then go to the trunk and cut the yellow/red yellow/black blue/red blue/black wires out of the harness plug. i left about 2" on the plug side just in case i ever wanted to use it again.. also cut and strip the black/red black/purple black/white and black/brown wires at the same distance.
now, i connected with simple butt connectors as follows:
yellow/red to black/red
yellow/black to black/purple
blue/red to black/white
blue/black to black/brown

now the rear speakers work! as you mentioned, it is a very short run to the front speakers, so find yourself 3-4 ft of wire and a metal coat hanger. after removing the kick panel, you will find the mid driver - for the sake i was being sure to connect to the right side of these wires, i removed the speaker from the kick pannel.
if you have tweeters, you will immediately notice that there are 3 wires here. + and - running to the speaker and then one wire running from the + side of the driver to the tweeter. since the tweeter and the driver are run in parallel with a "passive crossover" or capacitor, you will also need to run your speaker - from deck to the - of the mid driver AND the tweeter. on my drivers side, the tweeter - was buried in the harnesses where on the passenger side it was much easier to find.
I attached my front front output of my deck as follows:
deck front left output + to Grey/red
deck front left output - to Grey/purple
don't forget your tweeters - you will see a grey/green wire attached to the driver + (don't touch that). now find the grey/yellow wire (that is the tweeter -) and attach that with a splice connector or simply combine grey/purple with grey/yellow in one end of the butt connector (sorry for the over explenation - trying to appeal to all levels of installers).

as soon as you connect this, you will hear both the tweeter and the driver working.

right side is similar:
right deck output + to Grey/white (at the speaker)
right deck output - to Grey/brown (at the speaker)
right tweeters are the same color wires as left (grey/green + still connected to right speaker and grey/yellow somewhere either behind the speaker or in the close harness. connect as left side.


i don't mean to clog up your stuff Luke, i hope you can find some useful information here. this was my first time coming across this stereo configuration in 5 e30's so i assume it isn't very common and i also noticed that this configuration had the least direct information available.

as far as quality, i'm running an alpine iva d-106 and i think that with some high pass filters from the deck set at 80hz, i am impressed with the factory speakers. i will likely now just add 1 or 2 10" subs and leave it be. the factory speakers so far - seem powerful enough for such a small cabin.

[nash89_325i]

Luke - great post and thread! I read, and re-read... and read a bit more. Then I got 'er done. Mine is a very simple case, '89 325i with stock HU, no amp, no premium sound, no fader. Everything I needed to do was readily accessible through the radio slot, I didn't have to open up anything else.

It's all about finding the twisted pairs. I had to unwrap about 8 inches of factory tape... my setup worked just like this post led me to expect apart from the exact color scheme of the pairs. Mine are:

Yellow/Red - LF(+)
Yellow/Brown - LF(-)

Blue/Red - RF(+)
Blue/Brown - RF(-)

Blue/Black - RR(+)
Blue/Brown - RR(-)

Yellow/Black - LR(+)
Yellow/Brown - LR(-)

I did the battery test to verify the pattern, but the schema was pretty apparent based on which pair ran to the right front (all the others run toward the driver's side)

Power connections were exactly as you described, only other wrinkle was that the antenna - white wire that bundles with the antenna lead - is driven by the blue/white wire in my aftermarket unit rather than blue.

Hey - thanks for your help!

Also, I just went with a very basic Kenwood KDC152 - so even after buying some tools I'm in this for way, way less than a C-note!! I liked the "vintage" aspect of the original radio but the volume knob was static-central and had to be jiggled to get any sound at all. Thought maybe speakers were bad but they all work and sound pretty good - and the stock wire is excellent as you said.

[StereoInstaller1]

Thanks so much guys... It's so much work for my crazy old ass to type all that stuff out, I am really happy this has been so useful for so many.

Thanks!
Luke