Trying to fit a new head unit to mate's Audi A4 (P reg, 96) - took out
original Blaupunkt factory-fitted unit and fitted JVC one (not sure of
exact model numbers, can post later if needed).

The Audi has ISO connectors for power and the front speakers (only
central 4 connectors wird up in brown socket), so can get the unit up and
running, but only through the front speakers. The wiring loom has three
coloured connectors, blue, green and yellow, looking at the diagram on
the original head unit, found that the yellow connector had wires for
"Right rear", "Left Rear", two COM wires and another wire with a switch
symbol.

Tried to be clever and cut the wires out of this connector and wired the
RR,LR, and the COM wires to the brown ISO, but it didn't work - now I
have a mangled wiring loom and still no rear sound!

There are a load of wires on the blue connector, but I have no idea what
they do!

Can anyone help, or let me know where to look for info?

TIA

--
Shabs.