It sounds like 2 conductors and an aluminum foil shield. Can you get to both ends of the broken wire? If so, just connect (with solder and shrink tubing) the red wire to the red wire, the black wire to the black wire, and if the shield is aluminum foil, there's a bare wire hiding in there somewhere, so connect the two bare wires together.
If you can't handle soldering, have someone do it for you because in a wet environment, no other repair method will suffice. If you can't get to both ends of the wire, throw the whole thing away because you're screwed. ;-)
<Chas>
