Wiring a new head unit - confused

[iluvbrownale]

If it helps, I ashamed my man skills do not take me far enough to get this job done. But I have absolutely NFI which wire to connect to which. I have a T4 Transporter van with a late 90's cassette deck. I have just bought a basic Pioneer head unit to replace it with and of course the connector doesn't match (I must have got very lucky on the only ever head unit swap I've done).

So this is the connector that comes with the new head unit (yeah, crap iphone pics I know). Which ones do I connect to which? I know the purple, green and grey are all for speakers, so that's fine. But the remaining 4, well they don't match the ones in the dash at all, in fact, there's more in the dash than here



This is the connector from the back of the old headunit. Ignoring the speaker cables, there's 5 rather than 4 and the colours don't match.



that connector runs 20cm and connects to another connector and another set of wires, even more!

[Transporter]

The brown/red is ignition switch (30), red/blue is battery+ fused (fuse9 or 21, 15A), brown is battery negative. Grey/blue is headlamp switch.

That's for 2.5L 99-03 T4.

You could also use your multimeter and the wiring diagram which came with your new unit to figure out which wire connects where, it's not that hard.

[Sunny43.5]

There are some adaptors at accessorie shops for some model as well . Transporters method is the best have done it this way myself for an eternity as I have been through 3 T4,s and now 2 T5,s all have had the head units changed and upgraded etc.