I have a 2007 Ford Mustang, i am trying to route the power cable to the engine compartment to hook to the battery and am not sure where the hole is that has a rubber grommet, i read its somewhere in the firewall but not sure where exactly. can anybody help me?
I don't have the exact answer you wanted, but keep in mind you can purchase grommet kits from any parts store and drill your own hole wherever you want.
passenger side firewall, kind of up behind the dash. There is already a big wire bundle going through the grommet. You will have to take the front tire rear splashshield off to get at it from that side