chassis wiring

My friends 87 626 will not start. I traced the problem to a grounded wire. It's the wire that goes from the main fuse (40A) to the computer. This wire caused me to read a direct short to ground on the positive batt. cable. When I figured out where the problem was I thought that maybe the computer was bad, but when I disconected it I had the same problem. I know that the wire is WR(white w/ red stripe) at the begining and LR(blue w/ red stripe) at the computer, and there is a 10A inline fuse some where. What I don't know is where that fuse is or how to get to the whole length of the wire to find the problem. So if anyone could help I would be greatfull.