old gentex auto dimming mirror wiring

Hi Completely new to these forums and hoping someone can help me decipher this 16-pin Gentex wiring block. A bit of background - I bought this off ebay to retrofit my VW, and know that I only need two wires to make it work - ground, and 12v switched live. Whilst I have no problem in wiring the mirror in, I need some help finding out which wire is the 12v and which is the ground. A quick search on the net leads me to believe the GROUND wire is the BLACK/ GREY wire. Would there be any harm in moving through the others, connecting them to a power source until I find the right one? The mirror in question came with ONSTAR, which is useless in the UK, so a lot of wires will be redundant. Thanks for your help!

Yes!  Randomly connecting power to the wires could damage it.  I dont have a diagram handy for that mirror, but I'd be glad to look.  Someone else here may be familliar with it even.

Do you know what kind of car it's from? Looks like GM wiring to me but I'm not sure. It might be helpful to list the color of each wire you see in the plug, if you can.

Chris, in case you dont get on Directtechs,  interested in coming to the installer BBQ/PowWow at my shop this august?