Head unit output - is there a stock amp?

[tangcla]

Audio output from the headunit: does the stock sound system have an amplifier trigger input wire, and if so, which colour wire is this?
I ordered a Chinese Android headunit, and there is no audio to any of the speakers.
Tested it with my old Pioneer headunit and that works fine.
I've got a BMW to ISO harness, and the new headunit is to the ISO plug, so I'm not sure if the antenna or amp wire is required to power on the amp.

[Timm]

The amplifier is powered separately - but (as far as I can see) there is a trigger connection which is the WHITE wire.

Revtor will know for sure though.....

[tangcla]

The amplifier is powered separately - but (as far as I can see) there is a trigger connection which is the WHITE wire.

Revtor will know for sure though.....

Is that through the head unit harness?

[Timm]

Yes, the WHITE wire goes to the standard head unit:

https://www.meeknet.co.uk/e31/e31_95.pdf#page=541

[vgs]

I had that same problem with no audio until I powered that wire to turn on the amplifier. If I remember correctly on the head unit I used it was labeled as wire to power an antenna.

[tangcla]

Thanks all!

[revtor]

Timm and vgs are right. The white wire (pin 16) not only powers the AM/FM diversity antenna amplifier in the C-pillar but also the audio amplifier in the trunk / luggage compartment.