Line output converter wiring, S2000

I have a bose spare tire sub with a built-in amp I'm hooking up to my stock S2000 system. As some of you may know, the stock S2000 deck doesn't have any pins in it for rear speakers, but it is a 4 channel deck.

There is a guy named Lucid that makes an adapter so there would be a way to makes the connection for the rear outputs at the deck. I don't have time to order this adapter as my car is apart right now. I don't feel very comfortable soldering to the pins on the back of the radio, so I'm still contemplating on how to hook the sub up.

My next question...

LOOK HERE:

I have no wiring diagram for this thing from five years ago. How do I hook this thing up. What are each of the four wires on the left end designated for?

What is the single wire coming out by the RCA's and do I need it?

I appreciate all your help!

I called them and the company is now called Metra. "Metralink" was a line they sold many years ago, not anymore. I spoke with tech support and found out what those four wires are. He read the colors off in the same order as they came out of my connector.

Grey = right+

Are those the colors ususally used in car audio for left and right +,-? If not, then they are just specific to how Metralink wired their unit.

I was told that single wire by the rca's is a "floating ground", not a chassis ground. He told me if I have no audio on the sub, then I connect that to the shield on the RCA, which is a negative- and that will give audio. He said I probably won't have to use that wire though.