Im trying to put a simple sub/amp combo in the trunk of my Mazda 3s 4 door and im trying to find an easy, painless way to run the power cable from the battery to the amp...is there an existing hole i can use to run a 4 guage cable through, or do i have to drill/punch one. If i do have to make one, where is the best spot to do it? I think im gonna cry when i have to punch a hole in my new baby!!

 

Hey,
I just put in a self-amplified sub in my P5. I don't know about the 3, but there is a rubber grommet down in the passenger footwell of the P5 where a huge cluster of wires runs into the engine bay. I pushed a Bic pen through the grommet, unscrewed the cap from the pen and pulled out the ink cartridge, and then pushed the wire through the pen body. Once the wire was in the engine compartment, I pushed the pen all the way through, and removed it. This left a nice tight seal around the wire, and it was a lot easier to get it through the rubber. Take a look and see if you can use the same approach with your 3. Good luck!

 

Alright, amps in, everything works and stereo sounds great. There is a large rubber grommet right on the firewall right behind the glove compartment that is huge and has a bundle of wires running through it. I pulled it out, cut a hole just undersized of the 4 guage power wire and ran it through that and put it all back together...almost looks like it was designed to go together that way...beats punching another hole in the firewall and theres no doubt in my mind that it will stay weatherproof. Ive got pics of how it works if anyone would like to see them.

 

Great minds think alike... exactly the same approach I took with my P5.

A little silicone might be used around the grommet where the wire comes through, if anyone has any concern about weatherproofing.

 

this guy really did good on his M3..
i hope he does not get mad at me posting his link...

http://www.cardomain.com/memberpage/567041