Im running a dedicated power cable from battery to trunk for 2 amps and i just want to know if drilling a hole through the firewall is the only way to do it? What happens in 15 years when the hole gets rusted and coroded from the moisture even with a gromet?
2 amps is a pretty small current so it doesn't need a big cable - there are other cables passing through for the back lights, find out where they run and see if you can just ease another one through the gap,it might work with a little lubrication. Just don't try to poke anything sharp through the hole. There are special fish wires that electricians use to get cables through holes conduits, you could try one of those or at least see how they are shaped so you can use something similar - you'll only need a short fishwire you probably have to buy a 5m length if you want the real thing. Good luck.
Depends how much space you have and the gauge of the power cables. I had to drill a hole in my fire wall to fit my 0 gauge power cable. But I used a size were I had to force my cable through so there wouldn't be any gaps. But you don't have to worry much about rust. If you ever pull your carpet off, you will notice a lot of holes. There normally drain holes they will rust after a while but it's nothing to serious. I got a 87 Jag with rust around the drain holes in the trunk but it's still strong.
