Quote Originally Posted by grave77
well u missed the enable pin B, this enables the preamp of the CD connector to work, also the digital inputs you didnt use will not show the CD counter clock ( data, reset ... ), thats if I understood that u used the connector only can you describe more what you've done?
I tried connecting the enable pin B along with the audio signals, but there's still no sound. I'm now pretty sure that the back unit (it contains FM receiver along with an amp!) expects some sort of digital command from the head unit before it sends any sound to the loudspeakers. I heard a pop when connecting the enable pin, so I guess that the back unit turns itself on then, but it's not enough.

It probably would be possible to reverse-engineer the protocol between the head unit and the back unit, but that would be a pretty major project... Instead, I'll ditch the back unit along with the OEM head unit and replace it with a conventional amp. I can use the existing signal cable for the sound from the new head unit to the new amp and the speakers are wired as two pairs, so it should be just a fairly simple wiring job.

The only problem is the radio antenna, since the current antenna cable doesn't go to the dashboard, since the factory receiver is in the back... Why on earth did they do it this way, just to piss off the do-it-yourself stereo installers?