I've just installed a Sony MP40 Head Unit in an Aug 2000 Citreon Xsara 2,
using the Connects2 Display & Steering wheel adaptor kit. This replaced
the standard Phillips 22RC220/35Z Radio/Cassette.

It works great, but I am a little confused by the fact that the old Phillips
head unit had 3 multiblock connectors, whereas the Sony only actually uses
2. Therefore one of the multiblocks is left unconnected.

Anyone know what the 'unused' connector does in the original installation?

TIA

Andy