Thread: PC9 404 - Wires dont match up?

Dont know if i ordered the right one but the wires dont match fitting after market head unit?

As you can see...





Any ideas?

You only need to use 3 of the wires, earth, perm live and switched live. The others aren't used.

Cheers, but which is which?

The pins dont match where the wire go though

Multimeter will sort that problem out

I've tried them in different combos but still now power?...

Think got it sussed apart from the switch live. Which is that?

On the Audi loom:
Pin 8 - Earth
Pin 7 Perm live
Pin 4 switched live

Standard ISO layout
Pin 8 - Earth
Pin 7 switched live
Pin 4 perm live

So the adapter should swap 4 & 7 as Audi wire them back to front.
However if your Audi is 2000+ then you won't have a switched live on the Audi loom as Audi changed to CANBUS to control this function. So you either pair it with perm live and rely on switching the HU on/off manually or you need to wire one in from the fusebox. The fuse you need is Radio S-Kont.

Great. Thanks.

Next issue is rear speakers are not working?

Rear speakers are separately amped. You need to use the other part of the PC9-404 adapter to link the rear RCA's on the HU to the 20 pin mini ISO connector on the Audi loom, then connect the flying lead on the same adapter to the power antenna lead on the new HU

All done!! And rear speakers working.

Just have to turn off by HU and not ignition which is no big deal. Might put switch live in at some point.

Thanks again for you help