Ohhh, a signal to the battery. Well, you'd be best to just run a new ground, and a new wire to the batter/ relay/ breaker box whatever.

There's also an engine ground on the drivers side shock tower underneath all those wires. Freshin that up w/ a little sand paper, a new bolt and some dielectric grease.

Once you do that (and the aforementions things) you should be in good shape.