I've installed the towing baseplate, CoolTech harness and now I'm installing the Air Force One auxillary braking system. I'm to a point in the wiring where I need to run a wire and air hose through the firewall, but I can't seem to find the best place to go through. I see what I believe to be a very large grommet on the passenger side of the firewall that leads to a point under the battery tray. Is this the right place to go through or is there a better one?
2009 Essex 4508