Need Help Wiring Through Firewall

[colek]

I just bought a new amplifier and sub for my 2007 Pontiac Wave and I'm having a real hard time finding a hole in the firewall to feed the amp's power cable through to the battery. I've had my head under the hood looking for a stupid hole for hours and I can't seem to find anything.

If you can help me out at all, you're a lifesaver. Thanks so much!

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[AJM511 10+ year member]

If you really can't find a rubber gasket to remove in the firewall, you can drill a hole in the spot that you want it to come through, and find a rubber gasket for it at a hardware store.

 

[colek]

Where would you recommend drilling through?

 

[AJM511 10+ year member]

wherever is the least visible. I drilled behind the ebrake on my truck, and it runs right through the panels to the back seat. It depends on your car, it might be better to drill on the passenger side if there are more places to hide the wire. Be sure to run your Rca's on the opposite side of your car, away from the power wire, to eliminate any possible noise from it.

 

[colek]

Okay thanks for the help!

 

[SpeedEuphoria 10+ year member]

I think a lot of newer cars the main wires run through the front fender and then into the car on the side just in front of the door, whatever side the batt is on. If you take the fender off you'll prob see it easily. meaning they dont run through the firewall like the older cars did

 

[colek]

Yup you were right, just finished wiring the power cable through the fender and to the trunk. Thanks! And just as I got all pumped for my installation to be done.. I take out the head unit to plug in the RCA cable and there are no holes for it.. Talk about a let-down.. So does this mean I need to go out and buy an aftermarket head unit? Is there any way around that?

 

[SpeedEuphoria 10+ year member]

LOC Line Out Converter is what you need if you want to use a stock HU

 

[colek]

Got the LOC, but where should I wire the amp's remote wire to? I've read that it's possible to wire it to the fuse box and just stick in into a fuse that's only active when the car's running. What would you recommend?

 

[OmegaBunny 10+ year member]

You can do that but find one that is an accessory so that it comes on with the car not a constant. You don't want the amp running all the time. You can also slpice into an accessory wire.

 

[azphat12 10+ year member]

Go to walmart or autozone, and buy a test light. Maybe $5 or $10.

Take out the stock head unit. Turn your key to the on position.

Ground the test light and touch it to wires until the light on the testlight comes on.

Once the light is on, turn the key off.

If the light on the testlight stays on. Turn the key back on and move to another wire.

If the light goes OFF when the key is turn off....but then turns back on when you turn the key back on. That wire should work.

Then, while your at walmart or autozone, buy some T-taps. It will allow you to splice into that wire without cutting it.

 

[azphat12 10+ year member]

You could do the same thing in the fuse box if that is easier to access.

Depends on the car. My friend had an 08 Vera Cruz and the fuse box was a nightmare.

So we pulled the stock head unit and just tested wires until we found one that gave power with the key on...but with the key off there was no power.

We tapped the amp into that.

Just remember....the amp will stay ON when the key is on....not when the radio is on. Just remember that so you do not run down the battery.

Or you could buy a new head unit....

 

[OmegaBunny 10+ year member]

If it were me I would go with a new H/U. But if money is tight then just tap into a wire. You lose a little control over the sound but it is cheaper. Like AZ said watch leaving the key on without running the car, whether the radio is on or not because you will run your battery dead.

 

[SpeedEuphoria 10+ year member]

Just remember....the amp will stay ON when the key is on....not when the radio is on. Just remember that so you do not run down the battery.

Indeed,

except for me the last time I used the fuse box like I have in the past, I got noise(subs going crazy like a test tone) with the car on my deck switched off(even when I just turned the car off, seemed the radio lost power before the fuse box source I used did). I never had that issue before. So it would be best to have the remote come on/off with the radio, so finding one from the back of the HU would be best