Firewall Access for Amplifier Power Cable?

First, I have a 2000 Buick Century Limited. I've installed an amplifier and subwoofer enclosure in the trunk. All of the wiring is fine when I run the power cable over the roof of my car, everything works. To my question.....

I need to run the power cable that connects to my battery through a driver-side firewall (or passenger-side if necessary). I found one small firewall at the very top of the driver-side, but can't figure out where the cable that is already through that hole is running.

Is there any other firewall that would be easier to wire through to my dash/floorboard?

Thanks for the help,
Erik

Sorry for the quick bump, but does any one have any advice on this? I need to get this done today so I can go back to school.

Thanks again,
Erik

I hit a problem like this before. You can try feeding the amp power cable in through that rubber stopper inside the firewall (where you said you saw another cable). Slide the cable in a few feet worth. Remove the sound insulator under the dash, then look underneath with a flashlight. You shouldn't be able to miss it!
Another way to do this job is to forget about going inside the car and just trail the cable underneath, holding it up with plastic lock ties. Just make sure if you do it this way not to attach it anywhere near a hot component; exhaust pipe, bottom of engine, etc...

well on how find out where that hole leads to, if you cant find the wire after you feed it thru its probly blocked out of your sight from vent ducts. if you should happen to run into this problem, look from the inside of your car towards the fire wall and feel around for any holes. you should be able to find somethin useful but be sure not to knock any wires loose. also when you do find a way thru if you choose the firewall route i suggest runnin the wire across the middle of the car under the carpet(more concealed that way). good luck.