The "black plastic loom" is commonly known as the "docking connector". What you need is a crimping tool and some fresh pins from Digikey for that connector. And possibly a buddy to recrimp it all for you (or do it yourself).

Stu (Eutronix) can handle this, but you'd have to send him your car, and I think Fed-Ex would charge a lot for that. Probably easier to do it your self, or find a buddy.

Or get the pins (needed regardless), and take it to a reputable car audio shop, along with a colour-coded wiring chart (Search the BBS).

Cheers