The wiring schematic in the back of my Hayes manual (for my Subaru L-series) dosn't match with what I see when I remove the HU from the dash and examine the plug(s) and harness. I also appear to be one wire short of what the schematic is telling me. I understand I can work out which wires are "live" (need to buy a multi-meter or and LED indicator) but are there any other tips? Is there a more accurate source of wiring scematics? (the Hayes manual is published in the US, I think, so I would expect there to be differences).
Cheers

edit: I got my local Subaru dealer to fax me a copy of their schematic, and that dosn't match either.... it shows one extra wire????

I have an issue at the moment where i have installed a head unit into my 2002 subaru liberty and i am missing wire 14 in the connector. It is the one that apparantly powers up the antenna booster, i have terrible radio reception... Is this your issue?

you could solder a short piece of wire to each end of a d or c sized battery then tape up the battery and strip back about 1 cm on the ends of each wire and solder the ends to make a nice end/point. Then you can use that to test your speakers. and use a test light to find the powers in the plug.