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Firewall of 2017 Prius Four for sub and amps.

Discussion in 'Gen 4 Prius Audio and Electronics' started by DR4LUC0N, Jun 15, 2020.

  1. DR4LUC0N

    DR4LUC0N New Member

    Joined:
    Jun 15, 2020
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    Location:
    Connecticut
    Vehicle:
    2017 Prius
    Model:
    Four
    So I just got a 2017 Prius Four, as I'm planning out my gear to overhaul basically the whole system(except keeping the head unit) in the car.

    I went looking quickly today and I don't see any accessible firewall grommets for the power wires. How are you guys doing it? The space is so compact under the hood I'm not sure where to even start with it.

    Any advice, help, pics or videos that'll steer me in the right direction would be great. Most of the videos I find are of older Gen prius'.
     
    #1 DR4LUC0N, Jun 15, 2020
  2. Kytaez

    Kytaez Junior Member

    Joined:
    Jan 24, 2019
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    Location:
    GB
    Vehicle:
    2017 Prius
    Model:
    IV
    Hi!
    I'm in the same boat ATM
    Can't find a grommet and would like to avoid drilling through firewall. I'll probably will investigate further tomorrow to see if it's doable.
     
    #2 Kytaez, Jul 4, 2020
  3. DR4LUC0N

    DR4LUC0N New Member

    Joined:
    Jun 15, 2020
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    Location:
    Connecticut
    Vehicle:
    2017 Prius
    Model:
    Four
    @Kytaez After searching for a long time browsing through reddit posts and google and here, I finally found a 4th gen guide, there wasn't any pictures, it was just typed out. But basically, on the driverside under the steering wheel there's what's called a beauty panel, you need to remove it(there's 2 screws) and look up towards the center of the car along the firewall, you'll see a bunch of wires going through a grommet that's bigger then needs to be, I punched a whole with a long screw driver then took an electricians fish tap, tied nylon string to it, and fed the fish tape up through the engine compartment, tied the other end of the nylon string to the 4AWG power wire and pulled it through the engine compartment.I hope you understand what I'm saying.
     
    #3 DR4LUC0N, Jul 4, 2020
  4. Kytaez

    Kytaez Junior Member

    Joined:
    Jan 24, 2019
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    Location:
    GB
    Vehicle:
    2017 Prius
    Model:
    IV
    I spent good hour to look for anything o can get through the firewall, and eventually i did find a grommet on a passenger side. Long, sharp, 4mm thick metal rod made the way no probs. For me it was the best way i think. Amp fitted under passenger seat perfectly. Didn't had time for a pictures. My Gen4 is a Japanese import and it could be different to the UK wireing. I'm glad you found the solution.
    Is there any particular reason to keep the stock headunit in your Prius? I had to get rid of my one cos it talked a lot (Japanese)
     
    #4 Kytaez, Jul 5, 2020
  5. DR4LUC0N

    DR4LUC0N New Member

    Joined:
    Jun 15, 2020
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    Location:
    Connecticut
    Vehicle:
    2017 Prius
    Model:
    Four
    The features and seamless integration with the car, I'd rather not buy a new head unit and a Maestro RR2(yet, might in the future) but there's really nothing wrong with the head unit. Mine doesn't talk so I don't have to worry about that. The only gripe I have is the maps, I prefer to use Waze when traveling and it doesn't support it, but I have a popsocket and a popmount 2 on the vent next to the door and makes it easy enough, plus Waze talks through car speakers when I need directions.
     
    #5 DR4LUC0N, Jul 6, 2020
    krmcg likes this.
  6. thomassster

    thomassster Member

    Joined:
    Nov 2, 2015
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    Location:
    Colorado, US
    Vehicle:
    2019 Prius
    Model:
    XLE AWD-e
    already stated, you have to move the black panel under the steering wheel by your knees that has the little light held on by two screws. then you crawl down and look above the accelerator pedal, just above and to the right for the grommet. For the under hood side, best way to see that side is to remove the windshield wiper cowl. The grommet is very thick so if you are attempting to get a large gauge wire through, I made a special wire that starts out a small gauge and solder wires stepping up to your larger gauge wire. Put some grease on the wire to help slide through easy. I tried using some strong tape on a straighten out metal wire hanger and the tape never holds. Solder the wires help get through a large gauge much easier. I went from inside the car to the hood since inside the car side has a smaller circle.
     
    #6 thomassster, Jul 13, 2020
  7. JakeCastle

    JakeCastle Junior Member

    Joined:
    Dec 25, 2018
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    Location:
    berkeley, il 60163
    Vehicle:
    2016 Prius
    Model:
    III
    sure wish someone took a photo
     
    #7 JakeCastle, Jul 23, 2020
  8. thomassster

    thomassster Member

    Joined:
    Nov 2, 2015
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    Location:
    Colorado, US
    Vehicle:
    2019 Prius
    Model:
    XLE AWD-e
    sorry, these are old pictures i did not take of the grommet, but within the vicinity. The picture under the hood has a picture without the wiper cowl. I drew an arrow indicating where the grommet is. It is underneath some hard black tube piping. The picture inside the vehicle is the accelerator pedal, and I drew two red lines of the big cable harness that goes right through the grommet. This is directly above the accelerator pedal.
     

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    #8 thomassster, Jul 23, 2020
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