[BMW JA]

Found the black wire yesterday! Works!!!

[Dekero]

Just a small add on to this post.. for those of you who are unaware... You need to use a line level adaptor like the Audio Control lc2i pro, which resolves the lost bass our system drops out as you turn your volume up... BMW as well as many other manufacturers have found that by reducing bass output as volume increases it keeps people from blowing speakers... This is bad for after market amp/sub installs as when bass is reduced your nice expensive subs do not hit as hard..

To those of you above who used regular LoC adaptors... Your missing a lot of sound ...

Here's a link

AudioControl LC2i PRO 2-Channel Line Output Converter with Impedance Matching, AccuBASS, GTO, Audio Signal Sense, 12V Turn-On and ACR-1 Dash Remote Subwoofer Control https://a.co/d/1BcHzlq

[richardodn]

To summarize a bit, for cars with CIC head unit, radio on signal is supplied by pin 13 of the big quad-lock connector. It's a black wire.

That black wire supplies a signal to the noise suppression filter of the diversity antenna section and pin 10 of the HiFi amp connector.

For the Top HiFi amplifier, everything is controlled via the MOST bus. The amp connector only contains power (2), ground (1), speakers (9 pairs), and the 2 MOST optical connections. However you can still pull signal from the antenna's black wire.

If you do grab signal from the antenna wiring area, be sure to grab it from the chassis wiring side of the noise suppression filter.

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For switched power
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HiFi - The factory amp pulls all it's power from 30A fuse 105. As long as your current draw is minimal, you can grab power from the amp pin 5 red/yellow.

Top HiFi - Here, switched power is provided from 5A fuse 120. It's the red/black wire. (Red/blue is the high current wire.)

In either of these cases if you need a high current switched power, I'd recommend using those to control a relay.

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For unswitched power
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Typically, unswitched power is for the high current needed to actually power the amps. Most of the time you'll want to power the amp from it's own dedicated circuit. The HiFi amp gets all its power via the switched 30A fuse. The top HiFi grabs unswitched power from its own dedicated 40A fuse on the battery power distribution box. Your best bet here is to grab it off the battery distribution block binding post with your own fuse.


It's highly likely that all this holds true for all the later F25 models and head units.