So, I'm back trying to add in my Parrot bluetooth phone kit into my Chrysler Grand Voyager (2004). This has hit upon several big obstacles, the first of which, nobody online (Manufacturers, suppliers, etc) can decide on what the correct kit is needed for this car, some say SOT-046 some say SOT-086 and others say SOT-948. So I checked, and in the past I'd bought the SOT-046 (For my last Chrysler Grand Voyager 2004) so bought another one the same.
However this time it didn't work out, connecting it in, all went well, however the unit when trying to play audio through the speakers simply slightly muted the audio and no phone/Parrot audio at all.
I did a lot of digging, checking wiring diagrams, cabling, etc, and came to the conclusion it must be the wrong cable, so went and tried others, but all gave the same problem, that it didn't fully mute the radio and no audio at all went through.
Next step, I cut the cables on one of the SOT-046 cables and started to do my own testing, firstly by trying a manual connection from the radio to the car audio harness. This is when I started to find something strange. Disconnecting all the audio output cables (Verifying the wiring diagram online and on the Parrot wiring diagrams, so at least these added up) from the radio, and trying by connecting just one (Driver side right) pair. This didn't result in any audio output at all. Strange! I then tried each of the other pairs, checking polarity (Front left, Rear left, Rear Right) and none of them worked. I was now really confused. So connected them all back up again and they all started working. So it wasn't a fault, but almost by design. This makes me think (I already suspected this) that there is an amplifier somewhere in the car to drive all the speakers (8 speakers in total!) which is sometimes referred to as the Infinity sound system. I then tried connecting all speaker pairs up again and then disconnected a single one whilst the system was still on, and strangely that speaker didn't totally go quiet, it lost a little volume but not totally. Swapping which wires were connected or not seemed to produce similar results, but again disconnecting a single pair didn't stop a speaker from working. This confirmed what I suspected, these aren't true line-level outputs to an amp, they are more a digital output per channel.
This is my assumption anyway, and if this is truly the case then I'm going to struggle to feed in the analogue audio from the Parrot phone system.
Therefore a bit more investigation is needed I suspect, but that's my findings so far!