Astra H Van Stereo

[raceboy]

Long shot, but worth asking....
I've been tasked with adding a little 'rear fill' to the stereo in an Astra H van, basically a small sub and amp in the back.
We're keeping the stock headunit, and in the van it's only got front speakers....
So to power up the amp I was planning on using the rear speaker feeds out of the headunit to a speacker to RCA convertor as there are no RCA outs, but does anyone have a clue which holes in the multiplug are the 'rear speakers'?

[parapaul]

I can't remember off the top of my head - have a look on the AstraOwnersNetwork forum - it's one of the better ones, you should get a DIY or something on there.