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Discussion Starter #1 (Edited)
Firewall 4 gauge wire routing on Manual 2012 MZ3

Edit: 4 gauge wire routing on a 2012 skyactiv, no drilling.
While searching about PAC’s and LOC’s I found this method in the MazdaSpeed section posted back in 2009, figured I’d see if it worked before I drilled something to get a 4 gauge wire through the firewall to power my amp and subs. To my amazement it actually worked great, figured I’d add it to the skyactiv section because with all the hours I spent looking for a way though this method was never in the search results.
Here’s how to do it…
First (optional) get the drivers side of your car on jack stands so you can see what you’re working with. You’re looking for the steering column and the rubber grommet around it in the second picture

Next feed your 4 gauge wire down behind the battery until you can get it from under the car, you may need to reach up under the car to grab it

Once its out the bottom I held it up to the steering column grommet and had a friend mark the wire with electrical tape so I would know how much needed to be fed through the grommet. Once marked I tied a piece of rope to the wire and sent that through the engine bay to underneath the car as well to pull the wire back through.

Untie the rope and pull the wire out of the engine bay and bring it into the car. You'll be feeding the wire from inside the car through the steering column then to the battery. Find the steering column and pull the carpet out from underneath the black plastic protector. Your wire will be going through right where my finger tip is. Take a index car and fold it up long ways so it has some strength and feed it in between the foam and metal of the car as shown (This will stop the foam from binding up while feeding the wire through)

Now feed your wire through from inside the car, once you have about a foot through reach up under the car and make sure it’s not binding on anything before you feed the rest through, keep going until you hit your electrical tape mark.

Now attach the wire to the rope, try to tape the end so there is less flat surfaces to snag on things. It got snagged multiple times while trying to pull it through but eventually it will go. The second and third picture is the wire going from the grommet to behind the battery on its way to the top.

Once the wire is in the engine bay and you want to put on some plastic split wire loom for extra protection you just put a couple inches on at a time and push it back down behind the battery until you covered the whole wire and it touches the column grommet. Then pull the wire tight and zip tie and tape it off so there isn't any slack swinging around in your engine bay

Last thing to do, feed the wire up behind the plastic cover of the steering column, tuck it behind the clutch and over towards the door to start tucking the wires down the car towards your trunk

Now you have your 4 gauge wire ready to hook up to your battery and your amp without any drilling.

Like I said in the beginning, I found this in the MazdaSpeed section and was posted by “JONtheBOMB” so all credit should go to him, here’s his post where I learned this http://mazda3revolution.com/forums/...s/1767-amp-sub-install-factory-radio-loc.html
Since this works on Skyactiv’s and didn’t come up any of the searches on how to get through the firewall I just wanted to add this to the skyactiv section and save anyone the hours upon hours it took me to finally find a way to get through the firewall without drilling, hope it helps!


Heres a second option, and my original post, for smaller wires...

Step 1
Remove glove box (Sorry no pictures of this step but can be found on forum)

Step 2
Locate this clip behind the glove box and on the back side of the firewall where you’re trying to get through. It is attached by two Phillips screws and slide rails that slide out towards the passenger door. (Second picture already has blue wire I put through it)


Step 3
Remove the screws and slide the clip off. Bend back the foam and enjoy the easy route through the firewall.:yes:


Step 4
Feed your wire through and reattach clip making sure the foam doesn't roll up underneath it while sliding it back into place (I'm choosing to go above the ac line so the wire wont heat up, It’s the top of the two metals pipes. Found this pipe because when the ac is on it will be the only cold one)


For larger wires (sub system wires) I’m guessing that just taking a dremel to the plastic clip to allow for a little more room would work fine but seeing as I’m only installing LEDs as drls the clip fits right over the wire no problem and foam seals it up.

Hope this helps any who are looking!
 

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Thanks for this info. I used the steering column grommet exactly the way you showed here to run a couple of wires in my 13 3. It was easy using your method to get the wires through with out drilling any holes.
 

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I think it'd just be easier to just drill a hole lol
 

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Broke the plastic part on the steering column seems fairly hard plastic, howd you get it past it?

Might you have a picture of the fed wire?
 

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Broke the plastic part on the steering column seems fairly hard plastic, howd you get it past it?

Might you have a picture of the fed wire?
The pics in the first post show the wire pass through location from the inside of the car. What piece did you break?
 

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When I said Broke, i meant the dude that posted this thread. I wanted to see where the wire goes through on the bottom of the car, with the wire going through it.

Shortly after I posted I saw another post in another thread from broke explaining how to get the wire through.


broke said:
You dont have to remove the piece around the steering column or cut any insulation, just pull the carpet back. Its hard to see the grommet unless u have the car jacked up and are under it. If u have a section of 6 ga or something just start pushing it through from the inside of the cabin along the steering column where I show the index card and wire in my one picture. Once u got a foot or so through then look under the car for it. You may have to reach under to where u can feel the steering column come through the firewall to grab the wire. But once its through it will be a lot easier to find that grommet . If you have any more questions let me know

EDIT: I Completed this! It is a huge PTA!!!! I understand the pictures now, its was a bit confusing before hand.

Thanks for the Index card trick. I fed the wire from underneath the car and i used *another* index-card and taped it nicely to the wire itself, which for me worked very nicely to get the wire into the cab.
Sorry for the confusing posts.
I see why another hole in the firewall would be so much easier. I thought this steering column method wouldnt be this difficult, seems much easier said than done.
 

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Discussion Starter #9
@CodeGreen sorry, been busy and haven't been on the forum in months or I would of explained the pictures better to you. I made probably 20 attempts at feeding it through from under the car but there really isn't enough space to see what your doing unless you can jack the car up high enough. Finally said screw it and tried to feed it from the inside, it adds a few more steps like getting the wire back to the battery but I gave up trying to go from under the car.
 

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I recently tried this on a 12 3 skyactiv auto and it works as well. Although its a bit annoying with 0g wire, using thinner wire or rope and taping it together and running it through the interior of the car first to the engine is the easiest way i found. I did lift my car up but i probably didnt have to. As long as it goes through you should see it.

I removed a little of the rubber to allow it to fit through easier.


This is coming from inside the car through the steering column





Hope these can clarify some of the procedure issues some had with the above images
 

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I recently tried this on a 12 3 skyactiv auto and it works as well. Although its a bit annoying with 0g wire, using thinner wire or rope and taping it together and running it through the interior of the car first to the engine is the easiest way i found. I did lift my car up but i probably didnt have to. As long as it goes through you should see it.

This is coming from inside the car through the steering column
Is it possible to punch a hole through that big grommet, and run the cable through it?
 

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Sorry to resurrect an old thread, but I'm about to do a Water-Methanol install in my 2010 Speed 3 and am going to be using the steering column wiring trick. I'm surprised, however, to see that nobody has thrown a grommet around these power wires, or at least used some wiring loom to protect them. If one of them shorts out on the body panel right there because the wiring insulation is worn through, I think they'll have a bad day. Isn't anyone concerned about this?
 
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First Post, Necro Post.

For those looking for the easy way (and much, much safer way, IMO) to run power for an amp on the 2010-2013 platform, just use the AC passthrough behind the glove box. I just routed oversized 4g through there and was able to fit the plastic bracket back on with no trouble.

Remember, there is a secret screw on the bottom of the glovebox, and the only way to get at it is to remove the door. If you're small enough (like, child size), and have a tiny screwdriver, you don't even need to remove the glovebox. I am not, but you may have more luck.

Yes, it looks like ass compared to hiding it in the steering column grommet, but I didn't have to lift my car, and it was done in ten minutes.


One more thing: with either method, use some sort of wire protector (split loom, flexwrap, etc).
 
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