Drilling through the firewall

Hey guys, I have a 2014 Taco with the 4.0L. Have any of you ever drilled a hole through the firewall to add another wiring grommet? I'm trying to figure out the best place to do it without ruining anything inside or out. Thanks!

 

just run the wires through the factory grommets. Ive used the one above the drivers left foot easily.

 

I just use a wire coat hanger to poke a hole through the existing grommet where @HawkShot99 mentioned. I tape the wires to the hanger, poke it through, and use the hanger to pull the wires through.

 

Depending on what you're powering, you could even run the wiring down the firewall, underneath the vehicle, and then up into the cab through an existing hole in the floor. I've done this method in the past and made sure the mounting was solid and used that black corrugated wire shroud stuff to protect the wire. I don't regularly go crawling over rocks or bottom out on anything, so it worked for me.

 

I second what @Pigpen does. I use electrical tape to tape the wire end to a coat hanger to snake them through a factory grommet mentioned by @HawkShot99.

I also ran my CB coax cable through a different grommet not on the firewall, but still through a factory grommet, no new drilling here.

 

Stab this through, feed wire through, remove tool.

 

They sell these in the prison commissaries don't they?!?
That's on mean looking tool. Never seen one, but I am sure it would work great!

 

Sold as "Cellmate Core Sample Tool" at Ace Hardware.

 

When I restored my 55 chev, the firewall was swiss cheese... spent an inordinate amount of time welding and refinishing that sieve. My experience and gut say NO. Go through the factory grommet-lots of room there. Added benefit? Won't leak.

 

There is a small 3/4” grommet up above and sort of left of the main firewall boot. There is another one same size on the passenger side firewall above the AC line boot. Use either of those if you haven’t yet. They are super easy to run wires through.

 

See my pic below for grommet location:

The Daystar firewall boot with 2 loomed wire bundles comes out is where the factory 3/4” grommet is. I enlarged this hole and added the Daystar boot to be able to run more wires. I didn’t want to drill a whole other hole.


Otherwise I’ve left the firewall untouched.

 

This is an FJ cruiser but the red wire is going through the other 3/4” grommet I mentioned:

 

Thank you very much!

 

I added a DayStar boot immediately above the driver side factory location at about the 1 o'clock position by drilling a 1-1/4" hole with a stepped drill bit from Harbor Freight. Working great thus far. There's an image somewhere here on TW.

 

Is this the one?

 

That's my pic, I was thinking of this thread: https://www.tacomaworld.com/threads/wires-through-the-firewall-the-right-way.531829/#post-17041512

It's what I followed to add my own firewall boot. It was as easy as putting a block of wood between the carpet and the firewall inside the cab and then drilling through from the engine bay. I then used a file and some 60 grit sandpaper to deburr the hole, brushed on some touch-up paint, then inserted the boot once it was dry. No more fishing wires through the tight confines of the factory grommet.

 

Man, thanks so much! I can always count on somebody on here!

 

DIY or How to?

 

I don't have a really complicated write-up but I can explain the process.

Based on a cardboard mockup with my BlueSea fusebox and circuit breaker I knew I would need an aluminum sheet about 12x7 with one end bent upwards to bolt into the frame.

Normally I get my sheet metal from onlinemetals.com but for this I found an anodized aluminum roasting dish at Goodwill for $5 that was about 1/8" thick which was perfect for cutting up. I did the initial shaping with a battery-powered sawzall (a jigsaw would also work) and then rounded/sanded the edges with two grinders: one with a grinding disc and the other with a flap sanding disc.

From there it was just a matter of securing the fuse box and circuit breaker with self-tapping sheet metal screws. I did put the fuse box too close to the right so I have to loosen one screw and wiggle it out of the way to put the bolts in--forgot about that part.