Radio Wiring and Amp Bypass

[klavender1]

I just wish I had the skills to draw a diagram and show it on the computer...you guys kill me.

:-D Sorry! I'm sure when you've done it a thousand times it's easy. LOL. I can do most things to cars including "standard" stereo wiring. Of course I'm used to being able to buy a vehicle specific harnesses for other cars and it makes it easy. Now that I know I don't have an amp I will research it more.

[StereoInstaller1]

Your '86 has 2 wires going to the fader, plus a ground. After the fader is a main ground splice, but it still only has 2 speaker grounds at that point.

There is a ground splice right by your left seat, but running wires from there is a hassle, easier to use that pair of grounds as the rear grounds and re-wire the fronts completely if you want a simple way of dealing with it.

[LJ851]

I just wish I had the skills to draw a diagram and show it on the computer...you guys kill me.

Luke, just do it old school like i do. Draw diagram on paper, take a picture of it, post picture. done.

[klavender1]

Your '86 has 2 wires going to the fader, plus a ground. After the fader is a main ground splice, but it still only has 2 speaker grounds at that point.

There is a ground splice right by your left seat, but running wires from there is a hassle, easier to use that pair of grounds as the rear grounds and re-wire the fronts completely if you want a simple way of dealing with it.

Thanks! Just now saw your post after I got everything put back together.I used the wiring diagram posted on here. I wired up all the speaker positives from the HU to the positives going to the fader. Then shared the grounds. So left speakers' grounds on the HU to the left speaker ground coming from the car harness, and vice versa. Do you think that will be an issue? It all works and sounds better. Otherwise, it's hot outside. :D

[StereoInstaller1]

Yeah, you really need to have 4 separate grounds.

First, you are losing power, second, it will eventually overheat.

Neither is good.

[klavender1]

Your '86 has 2 wires going to the fader, plus a ground. After the fader is a main ground splice, but it still only has 2 speaker grounds at that point.

There is a ground splice right by your left seat, but running wires from there is a hassle, easier to use that pair of grounds as the rear grounds and re-wire the fronts completely if you want a simple way of dealing with it.

On my to do list for today. Thanks!

[bimmer630]

"Common ground" DOES work PERFECTLY with ALL aftermarket stereos, IF you use it properly. If you follow my instructions, it will behave flawlessly.


Luke

Yeah, you really need to have 4 separate grounds.

First, you are losing power, second, it will eventually overheat.

Neither is good.

Your confusing me dude. Maybe youre talking about two seperate stereo systems? I followed your directions and my speakers sounded like garbage with the common ground.

Not trying to be a douche but just tryin to understand your thinkin here

[racerjay88]

Luke,
So I read this entire thread and I tackled an install in my '87 eta. Head unit is Sony Explode (don't have model number in front of me) and 4 brand new Kenwood 4" at all four corners. I followed the wiring advice at the top of this thread and it worked for the rears sort of. Since I only have 2 pairs of wires coming out of my fader in the dash I used those two pairs as the rear left and right positive and negative. I then ran new wire for the front and they work fine. Have not completed the install yet (head unit is not mounted in dash) but wiring is done at the trunk with an Amp bypass and the Sony wiring harness is spliced to the BMW for power and such. I have one question now. I have no volume in the driver side rear speaker (Left rear) Pass side speaker has volume and appears to be working. Where should I start checking my wiring at the trunk Amp bypass bundle? Any suggestions?

[racerjay88]

I found my problem. traced the color wire from speaker not working and matched it up with the color coming from under the dash spliced into the Sony wire harness at the amp bypass in the trunk.

[StereoInstaller1]

Your confusing me dude. Maybe youre talking about two seperate stereo systems? I followed your directions and my speakers sounded like garbage with the common ground.

Not trying to be a douche but just tryin to understand your thinkin here

Just caught this post.

You are confused, and I am talking about 2 different stereo systems.

You are aware you caught 2 completely different installs being discussed, right?

You know you used those quotes completely out of context, right?

Both of those statements, when applied to the proper discussion/installation, are correct.


Either way, did you get your mess figured out?

[guibo09]

luke, my goal is to install an aftermarket head unit and build a DIY class-t amp into the original bmw amp case (preserve original connector and everything).

now, if i understand correctly, there is a common ground between the headunit and the amp? ie, there is only one ground wire going from the head unit to the amp?

so, is it possible to use the stock wiring between the amp and the headunit? i was thinking of simply soldering RCA terminals to the stock wires at the headunit side (with all the rca grounds connecting to the single brown/orange wire).

will this work? or do i really have to run rca cables with individual grounds?

[e30BMart]

lol rocket surgery. I have an aftermarket amp.. I know nothing about car audio so I'm wondering why the dash wire(s) are not connected to the speaker wire(s)... Why do you not put an "s" to wire? Do I need to buy a single aftermarket, dash and speaker wires ? I'm bringing my car to an expert tomorow, if he has never done an e30 before should he be able to figure it out? It seems the e30 is the only car with this kind of complicated wiring... My head is missing a piece of the puzzle because none of this makes sense. plus you have multiple wires connecting to the orange brown wires, how come?

anyways I guess ill have to go get ripped off by stereo guys

[StereoInstaller1]

What year/model is your car? Do you have "Premium Sound"?

Your local installer is NOT likely to figure it out without proper BMW experience, as these are unlike any other car.

[guibo09]

luke, any insight on my previous question?

can i use the original wiring between the head unit and the OEM amp as RCAs for an aftermarket amp?

[StereoInstaller1]

luke, any insight on my previous question?

can i use the original wiring between the head unit and the OEM amp as RCAs for an aftermarket amp?

Yes, you sure can.

If you do this project, post some pics up!