We usually run extras out through the existing loom seal above the accelerator. Easiest to remove RH headlamp etc, and lwr rt dash pocket fuse cover. Use a test light or sharp screw driver to piersc the gland, feed a draw wire through, solder to other wires and pull it back through. You will probably need to spray silicon, easy glide, or similar on the grommet. Use brazing wire if you can't get auto wire through.