Radio Wiring and Amp Bypass

[gath]

All done! got it figured out.

[Rontgen]

I want to do a factory amp bypass on a late ‘89 with premium sound with no fader. Is thing a good diagram to use?

Did this diagram work for you? I have an early build 1990 with premium sound and no external fader.

Thanks!

[gath]

Did this diagram work for you? I have an early build 1990 with premium sound and no external fader.

Thanks!

I used this and it worked out well.

[Rontgen]

Thanks!

[bpiersma]

Yeah, that works...not ideal, but it works. There are so many different setups in these cars its crazy, glad you got through it!

Luke

Luke, I have what I think is a somewhat unique issue. I purchased this 1991 318i convertible with a crappy aftermarket HU already installed (OEM speakers and trunk amp). Thankfully the original HU was in the trunk in a box. I've now reinstalled that, double checked all the wires, but am getting no sound whatsoever to the speakers. Antenna powers up, HU powers up, but no sound. It doesn't look like the previous owner did anything to the amp (original wires and connectors). Yes, there is power to the amp (12V). I think I have premium as there are tweeters in the doors. My objective is to use the original HU and speakers (go back to stock). Does it make sense to bypass the amp and use the original HU?

Other facts that may be interesting: I have all the seats removed along with various other components of the car (center console, taillights). I cannot imagine that affecting the speakers, but maybe I'm missing something.

Any thoughts or ideas? Thanks in advance!

[bpiersma]

Forgot to add:

There is no in-dash fader.

[cspec]

Did this diagram work for you? I have an early build 1990 with premium sound and no external fader.



Thanks!

Edit: This worked well for me!

[Flexx]

I used this and it worked out well.

I own a 89 325is with premium sounds, amp and no external fader and was wondering if that was all you did?

I have the same set up but my sounds good at start up but 2
Mins in the sounds starts to fade.

I have 4 sets of speaker wires, no orange/brown wires but the positive and negative wires wrapped both for front and back speaker wires to
Make it easy.

Did you follow the write up?

[bobdavisnpf]

bpiersma, sounds like you're fairly close to getting at the stereo wiring harness. If you can pull up the driver's side carpet outside edge, you can inspect for damage. You can pull the rear side panels to see the rear speaker wiring as well.

[thexfactord22]

Just did this today....This thread is bad ass, once you peel back the tape and find the wires twisted together its super easy!

[b1800e30m3]

Just tackled this for the last two days, car is a 1990 318i convertible with premium sound.
I followed bypass for the amp and have all my wires in the back connected to each other:

blue/red-grey/white, blue/brown-grey/brown, yellow/red-grey/red, yellow/brown-grey/violet, blue/black-black/white, blue/brown-black/brown, yellow/black-black/red, yellow/brown-black/violet.

then at head unit i have everything like op posted except one white wire going to amp that is not there is not connected and brown/black wire which i don't know where it goes? head unit powers up radio receives a stereo signal but no sound out of any speakers. PLEASE HELP

[parkerbink]

Check the fuse to the amp, failing that check the amp.

[b1800e30m3]

Checking now, it's just the amp that's built into head unit. Looks like a micro 10 amp, pulling and replacing it now

[parkerbink]

There is an oem amp in the trunk.

[b1800e30m3]

I removed the oem amp and did the bypass per insructed in this post.