Help Installing Powered Sub in my 2007 Focus

[NewSoundMan78]

Just wondering what the best entry point through the Fire Wall would be so I can get to the battery? Also is there an alternative spot to wire this to?

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[fasfocus00 5,000+ posts]

Auto or 5 spd?

auto - where the clutch pedal would go

5 spd - should be 3" to the left of clutch pedal or 3" above, double check by looking at the firewall itself

 

[NewSoundMan78]

Auto. Found this earlier but just don't want to drill. Kind of chicken! Is this the only place?

 

[keep_hope_alive Premium Member]

no alternate spot, must go to the battery directly. the power wire needs an inline fuse within 12" of the battery, the fuse holder should be firmly attached, you do not want the wire holding up the fuse holder. wire should be zip tied every 6-8" or so in the engine bay, and should be protected in split loom. where you penetrate the firewall, you need a grommet. grommet can be rubber or plastic, but you cannot let the wire insulation pass through a metal opening without a grommet. if you use a factory rubber grommet, you are fine. if you use a factory hole, you need a grommet.

lastly, make sure the hole is sealed, otherwise the power wire can wick in water and get your floor wet. i use a streetwires firewall grommet whenever possible. if not, i use a rubber grommet and silicone to seal the penetration.

 

[NewSoundMan78]

As far as that location goes the fuse box is over the top of it and I can't get to it. Can the Fuse box move?

 

[keep_hope_alive Premium Member]

you can't move the fuse box... too many wires there.

you don't need actual access on the firewall side.

here is the process:

locate a spot that is flat and open on both sides (you've done this).

buy a properly sized firewall grommet, streetwires makes some that are very nice, otherwise a standard grommet can work.

drill a hole perfectly sized for the grommet.

file off the sharp edges on the hole

insert the grommet

route the power wire through the hole and grab it from the engine bay. you can push the wire in the direction you need. note: do not just pull the wire from the engine side, you're likely to loosen the grommet. carefully push wire through from the cabin side, taking note of the grommet.

route the power wire away from heat and moving parts, routing with factory wires is good.

protect the wire in split loom and zip tie to keep firm

once you're all done, hit the hole/grommet/wire with some silicone