How do you run amp wire to battery through firewall of 2004 4runner?

Answer 1

Assuming that your amp wire is thermal wrapped (if not, get some thermal tape and wrap it up)

Drill a hole a little bit bigger than your amp wire in the fire wall. you are going to want to run this as close to the top of the underside of your dash as possible. then run the wire around the edge of your engine compartment, (there should be a good size ditch that runs all the way around) and connect it to the battery. zip tie the cable down tightly so that it doesn't move around (cut off zip tie ends as necessary for a clean look).

Then get a thermal rubber gasket to plug the extra space around the amp wire in the hole of your firewall. you can get this at any hardware store just grab one that looks like it will fit.