Best options for routing wires through firewall

[Doc3g]

New to automotive wiring and have been reading some posts but I've noticed a couple of different methods of getting the wires into the passenger compartment. I was reading one build thread and they used a Daystar firewall boot so I ordered the boot and 1 1/4 hole saw from amazon.

Then I noticed a couple of people using what looks like a weatherpack bulkhead kit (Amazon.com: Weather Pack Bulkhead Kit 22-pin 16-14 Ga.: Automotive)

Is one method superior to the other? The weatherpack route certainly looks like a lot more work than just putting wire loom over the harness and running it through the daystar boot.

If it matters, I'm planning on running ~ 12 wires, mostly 16 ga from relays in the engine bay to switches inside, most of which will be @ the radio location.

 

[thegipper]

I used the existing boot that is next to brake booster on the drivers side to run my amp wires and a few other ones. I used a utility knife and added a small slit in the boot and fed the wires through it there, no issues.

I wouldn't be a fan of drilling through the firewall to add a boot unless I was adding so many wires that I couldn't use an existing one.

 

[Kanoe]

Just say no to the hole saw. It belongs in the plumbing section.

As mentioned above, that existing hole is where the clutch would be in a manual I believe.

There is also a very nice existing grommet for use above the gas pedal that us 5 speed folks can use. Either one is adequate for what you are doing.

 

[brillo_76]

I would go through the engine harness route. As it's easy to get to and not in that water zone on the driver side. Water runs through the drivers side area big time. Hence why people poking holes through the boot for wires for amps etc end up creating a chanel for water to run through to your drivers floor kick panel etc.

Sent from my SM-J337V using Tapatalk

 

[cblock406]

Going back to the other thread you created, I think you are making this more difficult by not using the driver side. Moving brackets and cutting holes is not something I would do, but again, we all modify our rigs differently.

 

[jross20]

Man I was about to make a thread for this. Seems like such a pain compared to the 2nd gen tacomas.

 

[4Runner4Leon]

As others said, on the driver side you can use the existing hole for the clutch pedal, along with the Daystar grommet -

Here is a view from under the dash, it's the one with one large and some small wires running through it:

 

[Doc3g]

I would go through the engine harness route. As it's easy to get to and not in that water zone on the driver side. Water runs through the drivers side area big time. Hence why people poking holes through the boot for wires for amps etc end up creating a chanel for water to run through to your drivers floor kick panel etc.

Sent from my SM-J337V using Tapatalk

Sorry to be dense, but is the attached picture the harness you are referring to?

Going back to the other thread you created, I think you are making this more difficult by not using the driver side. Moving brackets and cutting holes is not something I would do, but again, we all modify our rigs differently.

haha, well, I actually tried your way again, ordered a sheet of plexiglass, a bunch of new high-current weatherproof relays from Fastronix, and a few other odds and ends but I can't see how to get blue sea box plus the relays plus the breaker onto the plexiglass and still be able to both close the hood and access all of the things on the driver's side of the engine bay. I think I could get just the bluesea box there but my endgame for wiring is going to require more than just that box and I'm not a fan of sticking the relays to the firewall. At least I gave it the old college try and have decided to keep the new relays, but I'm 99% sure the mount is going on the passenger side.

As others said, on the driver side you can use the existing hole for the clutch pedal, along with the Daystar grommet -

Here is a view from under the dash, it's the one with one large and some small wires running through it:

Thanks, that's what I've seen in several build threads and I've already got the boot. Where approximately is that located in the engine bay side?

 

[jross20]

As others said, on the driver side you can use the existing hole for the clutch pedal, along with the Daystar grommet -

Here is a view from under the dash, it's the one with one large and some small wires running through it:

Maybe I am blind, but where is this hole on the other side? (In the engine bay)

 

[4Runner4Leon]

Maybe I am blind, but where is this hole on the other side? (In the engine bay)

About midway between the existing wire grommet and the brake booster:

 

[jross20]

About midway between the existing wire grommet and the brake booster:

Er... maybe I had one too many last night, but I am 90% sure there is no hole there on mine.

 

[4Runner4Leon]

Er... maybe I had one too many last night, but I am 90% sure there is no hole there on mine.

Oops, my bad - the hole was not there, I drilled it with a hole saw. There is a flat area where the clutch pedal would go, and the sound insulation is perforated there, so it makes for a nice installation. But you do need to drill the hole .

 

[Kanoe]

There is an existing hole above the gas pedal with a factory rubber plug in it. Can’t see it from inside due to the padding. It’s a nice spot for wiring on a 3rz but on the v6 it might be difficult to access, I’ve never looked.

That daystar universal grommet is pretty great.

 

[Doc3g]

Oops, my bad - the hole was not there, I drilled it with a hole saw. There is a flat area where the clutch pedal would go, and the sound insulation is perforated there, so it makes for a nice installation. But you do need to drill the hole .

Did you drill the hole from the inside to the engine bay?

 

[Devbot]

Er... maybe I had one too many last night, but I am 90% sure there is no hole there on mine.

Ironically I got a hole but no boot! Learn something new every day

 

[jross20]

Oops, my bad - the hole was not there, I drilled it with a hole saw. There is a flat area where the clutch pedal would go, and the sound insulation is perforated there, so it makes for a nice installation. But you do need to drill the hole .

Oh snap. How does one do that without screwing it up? Haha

 

[4Runner4Leon]

Went in from the engine bay side to most of the chips out of the interior. Just drill slow and steady .

 

[jross20]

Went in from the engine bay side to most of the chips out of the interior. Just drill slow and steady .

Man that makes me nervous.. how did you get a drill on there? Doesn't seem like there's a left room, and do you recall what kind of bit that you used?

this is definitely one of those things I would prefer to pay someone to do just because I don't have much experience with drilling through metal

 

[mtbtim]

On my 98, I used an existing hole in the firewall plugged with a plastic plug. I used a grommet identical to the one [MENTION=198376]4Runner4Leon[/MENTION] mentioned.

*11/4” Universal Firewall Boot
Amazon.com: Daystar, Universal Firewall Boot, Single, Accommodates 3/8" to 1" Diameter Wire Bundles, fits any vehicle that needs a wire loom, KU20040BK, Made in America , Black: Automotive


This video will show you which hole I'm talking about. Start watching the video below at play time 25:21.


<iframe width="560" height="315" src="https://www.youtube.com/embed/fT_2szdKXRM" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

 

[4Runner4Leon]

Man that makes me nervous.. how did you get a drill on there? Doesn't seem like there's a left room, and do you recall what kind of bit that you used?

this is definitely one of those things I would prefer to pay someone to do just because I don't have much experience with drilling through metal

I used my bimetal hole saw set with an 18V cordless drill - lets you drill slow with gobs of torque, ideal for hole saws. But for sure, if you're not comfortable, this is not the ideal place to learn. Drill some holes on a scrap piece first to get the hang of it.