It would be much simpler and better to just run the wire directly from the battery to the amp. I would assume that your putting the amp as close to the battery as possible, likely under the false floor in the rear. There is no need to go through the firewall, all that is there is a jump start point. I would also recommend upgrading the ground wire, it is VERY thin and will make a big difference when upgraded.

I have both of my amps within a foot or so of the battery. Though only one of them installed in this pic.

 

That helps a ton... I honestly didn't know the battery was in the back. Thanks for the help.

 

NP, I thought that might be the case, so found a pic to show the location. Glad I could be of help.

 

I'll be replacing that ground this weekend.

 

Yeah, the battery location on these vehicles is remarkably convenient for Car Audio. Haha.

 

Running an additional 1/0 ofc wire will help. Run it through the passenger side where the others go through. Don't forget to upgrade the wires to/from the alt.

 

ofc wire?