Running power for a sub thru the firewall

[househead]

So I'm going to mount my InPhase USW10 sub behind the passenger seat (for now). I know all about computer firewalls but nothing about car ones 

I want to connect the sub directly to the battery (decent guage wire with a 10A inline fuse + a "P-cont" control wire from my HU, which I think is the same as the blue wire for the aerial?).

I think I've located two tubes-worth of cables behind the battery going from the engine bay into the interior. Any tips for effective feeding of cables through this and trim removal tips from the inside? Which bits do I take off on the inside?

Regarding mounting, I have some very strong velcro tape or there are some basic mounts and screws on the sub. Anything existing which this can be attached to without too much hassle? The velcro will hold but I also think it will rattle somewhat.

[Call the midlife!]

If you carefully make a small hole in the grommet for the main loom and push something like a biro outer through it you can feed your power line through there.
You need to remove the passenger bin door, side panel and bin liner (be careful with the roof drain bags).
Might be easier with the battery out but I used an extending claw pickup tool to grab mine.
If you remove all the passenger side trims, (seatbelt trim, door sill trim and the first one in the footwell) you can feed the cable along and across up in the dashboard.
Some have gone along inside the centre console but you'll always have some wire showing that way unless you lift the carpet.
Can't help with fastening the unit as it's different to mine.


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[househead]

Cheers mate, very helpful as ever! I think I'll attack it this aft/tomorrow. Will update with how I get on.


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[Call the midlife!]

If you've got enough cable consider running a spare with enough length to get to the frunk, you never know what you might want in the future and it'll save time and effort and broken clips.[emoji23]


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[jvanzyl]

Step
1 - disconnect the battery
2 - put passenger seat all the way forward
3 - open the storage compartment behind it and remove 7 screws ( 3 in the door, 4 in inside the compartment)
4 -next remove the side plastic (big curvy piece with two plastic attachments - you basically pull them directly out till they pop)
5 - Then lift out the bottom tray (now that the 4 screws are out in step 3)
6 - Unplug the ECU (it's right back against the firewall)
7 - reach to the right where the ecu cable goes through the firewall and push the rubber bung through into the engine bay
8 - go rough to the engine bay and lift out the loom and bung, and make a nice neat slit with a stanley knife max 1.5cm long.
9 - run the power cable though between the Sub and the battery, insert it through your nice slit in the bung
10 - put it all back together 


So with the battery disconnected and removed

[househead]

That sounds foolproof Cheers chaps. Gonna sail through this now thanks to yous. Lot more optimistic now anyroad!

[Call the midlife!]

If you haven't already then consider one of these, really handy when you're fiddling with the electrics, unless you're taking the battery out anyway.
Others are available elsewhere possibly cheaper.
Car Battery Isolator Switch Battery Power Switch Battery Leakage Switch 6-24V https://www.amazon.co.uk/dp/B07J34S5DH/ref=cm_sw_r_cp_api_i_1Db-Cb51WH1C7


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[househead]

Nice, good call. Saw one of those on a YouTube, looks handy as.


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[househead]

Just one other thing before I attack this today, I'm still not 100% on the wiring so wanted to confirm a few things.

I'll be using rca cables for audio, but the sub takes a "P-control" which is a blue wire on the sub loom. From what I understand, this is power from the head unit, required so that the sub is only powered when it needs to be (since it's connected directly to the battery).

Which wire on the Toyota (non-amp) ISO connector would I splice? Or failing that, which wire on the toyota loom which the ISO connects to?

In addition, I would like to do the radio aerial switch mod (using passenger window lock button) at the same time, so would like to ID that wire too.

I'm looking at this wikipedia page...

https://en.wikipedia.org/wiki/Connectors_for_car_audio

Can anyone confirm is these quoted wire colours are correct?

---
Antenna: blue.
Amplifier remote turn on: blue with white stripe.
--

And if so, would that apply to the toyota loom side or the ISO connector side?