Radio Wiring and Amp Bypass

[Vdubmt]

I figured it out. Was very is simple. I tested the negative wires to see which one went to what speaker. I was having a brain freeze there for a minute. Once I pulled the speakers and seen what wires went where the rest all fell into place. Thanks for the help and for this awesome thread.

[StereoInstaller1]

I have to the point that yellow and blue go to the back of the radio and the remaining 4 go behind the cluster. I do not have premium system. It seems that it should be a no brainer

Yours sounds like running new wires might be easier for you.

I have seen some that the ground junctions for the front and rear are under the drivers seat...so running extra wire to that point would be dumb, as it would be just as hard as a full re-wire.

[Vdubmt]

All of the wires where behind the radio. Didn't have to run anything. The grounds were not spliced off of the fade switch. They were spliced off of the radio wires. Very simple once I realized that. I was so concentrated on the fader that I over looked the rest of the wires.

Yellow/red+ driver front
Yellow/brown - driver front
Yellow/black+ driver rear
Yellow/brown - driver rear
Blue/black + pass rear
Blue/brown- pass rear
Blue/red+ pass front
Blue/brown- pass front

[CB-M3]

I think most people just don't peel back far enough to see the twisted pairs. Once you find the pairs it is pretty evident which are the grounds.

[Vdubmt]

Could be but in my case, the twisted pairs did not come off of the fader. Instead they came off of the wires that were connected directly to the rear of the radio. Once I realized that I tested the wires to see what ground went to what speaker. Very simple.

I think most people just don't peel back far enough to see the twisted pairs. Once you find the pairs it is pretty evident which are the grounds.

[StereoInstaller1]

All of the wires where behind the radio. Didn't have to run anything. The grounds were not spliced off of the fade switch. They were spliced off of the radio wires. Very simple once I realized that. I was so concentrated on the fader that I over looked the rest of the wires.

Yellow/red+ driver front
Yellow/brown - driver front
Yellow/black+ driver rear
Yellow/brown - driver rear
Blue/black + pass rear
Blue/brown- pass rear
Blue/red+ pass front
Blue/brown- pass front

Yes, sounds like you found them

[Quinthirty]

Hi, I'm a newbie at this. Just wanted to make sure that I got the wiring right on mine as I got to take out some portions of the dash and wanted to check out the aftermarket wiring. PO put in an aftermarket Blaupunkt but sometimes there's popcorn, and the stereo power automatically shuts off when it reaches a certain volume (like a rev limiter?)

Now for the wiring. There seems to be four wires that are loose. According to the HU's diagram, they are the power sources. These are:

1. Brown
2. Red / Green
3. Green / White
4. Purple / Yellow

Just trying to match it with the inputs on the 1st page, and I think I got the 1st two right. I'm unsure of the last two wirings as my model is different. For all intents and purposes, its an '88 coupe & does not have premium sound.

Thanks R3v. Luke, you rock!

[Quinthirty]

One more thing about my car stereo is that the PO seemed to have set it up in such a way that the radio would power up even if there were no keys. So its like directly connected to the battery of the car. I wanted to change that.

Going back to the four wires above, I referred to the guidelines on page 1, and managed to power up the stereo at position 1, and eliminated the possibility of discharging my battery when parked for a few days / weeks. What I noticed though was that every time I got to position 1, when the power would kick-in, the clock would reset to zero. However, all other settings would be retained.

I went back to the 4 wires, exchanged Red / Green with Purple / Yellow on both power sources indicated in the HU (unswitched & ACC / position 1), and now its back to the former set-up.

Questions:

1. Can I not power the stereo on position 1 only without resetting the clock automatically? If yes, is there something wrong with my stereo that it doesn't retain clock settings?

2. Are E30 stereos really wired this way, that the power source is direct to battery?

3. Should I re-do / revisit the wiring as the PO did a hack job with the install?

[MrDomino]

I'm another person trying to figure out the hack job done by a previous owner.

1987 325is (Premium sound)

So I took out the gauge cluster (I had to do it for something else anyways) and stripped back the wiring a bit and found nine wires.

1. Brown/Black - Ground?
2. Red/Green - 12V unswitched
3. Gray/Purple - 12V accessory
4. Yellow/Red - Front Left
5. Blue/Red - Front Right
6. Yellow/Black - Rear Left
7. Blue/Black - Rear Right
8. Gray/Red - not sure
9. Brown - Another ground?
10. White - not sure

I've stripped enough back that I'm now behind the gauge cluster so I don't think going further is going to find me these twisted pairs that everyone has.

I then went to the back of the car and checked and the amp is still there. I have the following wires running into it.

1. Black/Purple - LR speaker+
2. Gray/Brown - RF speaker+
3. Gray/White - RF speaker-
4. Black/Brown - RR speaker+
5. Black/White - RR speaker-
6. X
7. Black/Brown - LR speaker-
8. X
9. X
10. Brown - Ground
11. Black/Red - Power input
12. X
13. White - Power input
14. Yellow/Black - Fader Left (from front of car)
15. Yellow/Red - Fader Left (from front of car)
16. Gray/Purple - LF speaker+
17. Gray/Red - LF speaker-
18. Black/Brown - Ground
19. Blue/Black - Fader Right (from front of car)
20. Blue/Red - Fader Right (from front of car)

So where do I go from here? Do I not use any grounds? Do I have to run new lines? I'm not sure where to go since I'm not seeing the twisted pairs.

As added incentive- if I do get this figured out then I'll write up exactly what I did with pictures so that others can benefit from it.

[MrDomino]

So I found another thread on E30 tech where StereoInstaller1 replied to someone else having a similar issue.

http://www.e30tech.com/forum/showthread.php?t=91268

It sounds like I can retain the stock amp and then just connect into the following wires to the speaker positive inputs on the new headunit and then connect the grounds to the chassis.
Yellow/Red - Front Left
Blue/Red - Front Right
Yellow/Black - Rear Left
Blue/Black - Rear Right

Does this make sense? I realize the stock amp isn't that great but the car is mostly gutted and used for track days. The only reason I want a stereo is because the 5 hour drives to the track suck when you can't listen to music.

[StereoInstaller1]

Hi, I'm a newbie at this. Just wanted to make sure that I got the wiring right on mine as I got to take out some portions of the dash and wanted to check out the aftermarket wiring. PO put in an aftermarket Blaupunkt but sometimes there's popcorn, and the stereo power automatically shuts off when it reaches a certain volume (like a rev limiter?)

Wow, sounds horrid. No, there is no "volume limiter", nor should it shut off, but your PO likely wired it wrong enough that the impedance is too low (4 ohms is a normal speakers' "load", zero ohms is two wires tied together, a dead short, and it sounds like it is wired to 2 ohms!)

All that crappy noise should not be happening, either.

Since you have to gut this whole mess, you may want to try a "bench test" in which you use a speaker and some adequate 12V power supply, whether it is a 12V battery, a "power pack" or a proper power supply.

Get the thing wired and running on your work bench, test the hell out of it.

While you are testing, you may find you have one of the weird-o Blowchunks (er, sorry, Blaupunkt) that will turn on with the key off, as modern BMWs, most VAG and all MBZ do. You can turn the deck on with the key off, but then, like freaking magic, they will turn on and off with the key, too.

Find your owners manual, get a grip on the feature called "FIX VOL" too, it is bad ass and should be law on all stereos everywhere to have.

Now for the wiring. There seems to be four wires that are loose. According to the HU's diagram, they are the power sources. These are:

1. Brown
2. Red / Green
3. Green / White
4. Purple / Yellow

Just trying to match it with the inputs on the 1st page, and I think I got the 1st two right. I'm unsure of the last two wirings as my model is different. For all intents and purposes, its an '88 coupe & does not have premium sound.

Thanks R3v. Luke, you rock!

OK, now is where once again, I say GET A TESTLIGHT PLEASE! There is a fine one at Wal Mart for $5. Do NOT use a meter, use a test light. Meters can read wrong when used in a situation like this and $5 will save your bacon, just do it, OK?

Here is what you should do:

Grab your test light and make certain what YOUR wiring is. A nice thing about this is that you can use this on ANY car made before 1999, pretty much.

The first thing to look for is the "constant voltage". Goes to Yellow on virtually all aftermarket decks (Mid 80's Pioneer is a good exception) Clip the test light to the ground wire (big brown wire) and start checking for voltage with the key off.

If none of them work, see if your test light can reach something known to be a working +12V. I have been known to pop off a dome light cover and test voltage there, especially on cars that use the same fuse for radio constant and cigarette lighter (BMW, GM, some Ford all do, generally) power.

So, first, make sure you have a solid ground and a solid +12V and connect that yellow wire to it. I recommend crimp connections and a proper crimp tool, you can get the same one most pros these days use for $20 at Home Depot.

Now that you know which wire is constant and it is connected to the decks harness, do the dash light wire, either so you can use it or insulate it. This is a tricky wire, as it will show as ground (especially on a meter, put that thing away!) when the lights are off, causing what we call "Daylight Radio".

Got an orange or orange/white wire on that deck? This is where it goes.

To test to make sure it is the right wire, turn your dash lights on by pulling your headlight switch out and look to see which wire lights up. Rotate to make sure you have the right wire, it should change voltage (test light brightness) with the dash lights. Nissans get weird on this, HMU if needed.

Once you have nailed your constant circuit and illumination (BTW, most decks simply get dimmer with the lights on) you should have a solid grip on what to do to find your "ACC" wire, right? Turn that key on and look to see what powers up!

The real advantage in test lights is fuse checking. Using a test light is a very smart way to see if the fuse is good, as you will know if the circuit is live or not! I have seen plenty of cars that the fuse was fine but that branch of the fuse box was dead. "WTF, the fuse is good, I put a new one in and I still got no power" is very common to hear around stupid installers. Don't be stupid!

One more thing about my car stereo is that the PO seemed to have set it up in such a way that the radio would power up even if there were no keys. So its like directly connected to the battery of the car. I wanted to change that.

Going back to the four wires above, I referred to the guidelines on page 1, and managed to power up the stereo at position 1, and eliminated the possibility of discharging my battery when parked for a few days / weeks. What I noticed though was that every time I got to position 1, when the power would kick-in, the clock would reset to zero. However, all other settings would be retained.

I went back to the 4 wires, exchanged Red / Green with Purple / Yellow on both power sources indicated in the HU (unswitched & ACC / position 1), and now its back to the former set-up.

Questions:

1. Can I not power the stereo on position 1 only without resetting the clock automatically? If yes, is there something wrong with my stereo that it doesn't retain clock settings?

2. Are E30 stereos really wired this way, that the power source is direct to battery?

3. Should I re-do / revisit the wiring as the PO did a hack job with the install?

You can count on hackery, pull it apart and make sure each speaker has 2 wires going straight to the deck and that those 2 wires do not connect to any other wires at all...you cannot share a speaker ground at all if you want proper operation.

BTW: pay attention here...this rule changes if there is an amp involved, stay tuned!

If I had the car here, I would take all of the wiring apart and re-do it. It sure as hell should not shut off, but the "key off operation" may be one of your decks "features". RTFM!

Luke

[StereoInstaller1]

I'm another person trying to figure out the hack job done by a previous owner.

1987 325is (Premium sound)

So I took out the gauge cluster (I had to do it for something else anyways) and stripped back the wiring a bit and found nine wires.

1. Brown/Black - Ground?
2. Red/Green - 12V unswitched
3. Gray/Purple - 12V accessory
4. Yellow/Red - Front Left
5. Blue/Red - Front Right
6. Yellow/Black - Rear Left
7. Blue/Black - Rear Right
8. Gray/Red - not sure
9. Brown - Another ground?
10. White - not sure

I've stripped enough back that I'm now behind the gauge cluster so I don't think going further is going to find me these twisted pairs that everyone has.

I then went to the back of the car and checked and the amp is still there. I have the following wires running into it.

1. Black/Purple - LR speaker+
2. Gray/Brown - RF speaker+
3. Gray/White - RF speaker-
4. Black/Brown - RR speaker+
5. Black/White - RR speaker-
6. X
7. Black/Brown - LR speaker-
8. X
9. X
10. Brown - Ground
11. Black/Red - Power input
12. X
13. White - Power input
14. Yellow/Black - Fader Left (from front of car)
15. Yellow/Red - Fader Left (from front of car)
16. Gray/Purple - LF speaker+
17. Gray/Red - LF speaker-
18. Black/Brown - Ground
19. Blue/Black - Fader Right (from front of car)
20. Blue/Red - Fader Right (from front of car)

So where do I go from here? Do I not use any grounds? Do I have to run new lines? I'm not sure where to go since I'm not seeing the twisted pairs.

As added incentive- if I do get this figured out then I'll write up exactly what I did with pictures so that others can benefit from it.

Ok, so this car is a perfect example of "make a plan".

You could, if you wanted better sound, bypass your stock amp. You would use the stock input wires (yellow/red, yellow/black and Blue/red blue/black) connected to the rear speakers at the amp and run all new wire to the fronts...however, if you KNOW you are doing better than that, you should just use the stock amp until you do your 5 channel setup.

No sense wiring and then un-wiring, right?

Hope this clears up some confusions

Luke

[MrDomino]

Ok so if I do retain the stock amp then I just connect into the following wires to the speaker positive inputs on the new headunit and then connect the grounds to the chassis and don't worry about connecting the speaker negatives at all, right?
Yellow/Red - Front Left
Blue/Red - Front Right
Yellow/Black - Rear Left
Blue/Black - Rear Right

Just to reiterate- this is a 1987 325is that doesn't have the twisted pairs.

[MrDomino]

The diagram isn't complete yet. I'm eventually going to show the speakers to the left of the amp.

[MrDomino]

Updated picture:


Some things that I need to have clarified.
1. Is this actually the right wiring setup.
2. What does that white wire coming out of the amp do? Where does it go?
3. Where does the brown wire coming out of the amp go? Is it one of the two that I'm seeing at the front of the car?

I'm going to draw up one for what the wiring should look like if you want to delete the amp once it's confirmed that this one is right.