Wires through firewall

[eds72]

I'm sure the answers are here, probably multiple times but I seem to be struggling to find the magic combination of search terms that gets me relevant results.

I am pulling my JBL system and replacing with aftermarket components. I would like to run power from the battery to the amps - one under passenger seat and the other in RR quarter panel (same spot as factory JBL amp). What is the best way to route these wires? I assume I'd want to cross the firewall and enter on the passenger side? I see an easily accessible grommet with an extra nipple I could cut and use, but there's too much crap under the dash to see where exactly that enters.

I suspect there's probably an easy answer, I'm just thinking of the old "measure twice cut once" rule and applying here. I really don't want to cut anything until I'm sure it's the best location to use.

 

[Junior73]

In the past I have used a coat hanger, long piece of stiff wire to locate stuff, might help with fire wall cunundrum...

 

[eds72]

In the past I have used a coat hanger, long piece of stiff wire to locate stuff, might help with fire wall cunundrum...

For sure, I am just hesitant to cut a slit in the grommet to go fishing. Hoping someone can advise on the best location to cut before I fish stuff through.

 

[Sisente]

For my 03, there are a few grommets under the hood, on both passenger and driver. I pulled the small one, about the size of a marble (maybe slightly smaller) and ran my power through there. Was able to fish it down under the dash, to the radio, down through the shift console, and under the passenger seat. Took me a little while to pull it, but I wanted everything hidden.

 

[chillaxing]

I just cut the nipple off of the gromet on the driver side and pushed it through. This is the easiest and cleanest way. Extra pair of hands would be great. I fitted a 1/0 welding wire through. The gromet will probably come off as you doing this, but just put it back in its slot when you got your cable through.

 

[eds72]

I just cut the nipple off of the gromet on the driver side and pushed it through. This is the easiest and cleanest way. Extra pair of hands would be great. I fitted a 1/0 welding wire through. The gromet will probably come off as you doing this, but just put it back in its slot when you got your cable through.

If I come in on the drivers side is it challenging to get the wires to the other side once they are in the passenger compartment? Seems like it would be easier to cross in the engine compartment?

 

[chillaxing]

If I come in on the drivers side is it challenging to get the wires to the other side once they are in the passenger compartment? Seems like it would be easier to cross in the engine compartment?

No challenge at all. I ran the 1/0 right pass the firewall into a distribution block with 4awg going to my amps under both front seats. I did this so I can have the shortest run to my sub amp, plus I want easy access to the distro block just in case a fuse popped. Luckily I this, cause the other day, I was tuning my system and I popped one of the fuses. You can go with the passenger side but it seems you would need to take off the vent under the glove and the glove compartment just to get to it. But all depends how you are wanting run the cables, to determine which side is going to be best for you.

edit: How I ran the wire from distro was, up towards the fuse box then under the steering column towards the center console, then back down towards the firewall, ran along the fire wall, tucking everything in the carpets and vents.

Times like this is where I wished I documented my whole install.

 

[eds72]

No challenge at all. I ran the 1/0 right pass the firewall into a distribution block with 4awg going to my amps under both front seats. I did this so I can have the shortest run to my sub amp, plus I want easy access to the distro block just in case a fuse popped. Luckily I this, cause the other day, I was tuning my system and I popped one of the fuses. You can go with the passenger side but it seems you would need to take off the vent under the glove and the glove compartment just to get to it. But all depends how you are wanting run the cables, to determine which side is going to be best for you.

edit: How I ran the wire from distro was, up towards the fuse box then under the steering column towards the center console, then back down towards the firewall, ran along the fire wall, tucking everything in the carpets and vents.

Times like this is where I wished I documented my whole install.

Thanks, sounds like it's doable but truthfully... I'm really intrigued by the grommet on the passenger side. I'm not as young as I once was and am a little ham handed, so routing wires under the dash doesn't appeal to me. If nobody weighs in on that passenger side entry point I will probably end up slicing the grommet and attempting to fish something through. If it doesn't work to my liking it's easy enough to seal it back up with some silicone.

 

[chillaxing]

yup, just do what you think is easier for you. If you decide on the driver side. Its not as tight as you would think, since you will have all the panels off anyways.

You probably know this, but make sure you have a fuse in your cable no more than 18" away from the battery.

 

[eds72]

yup, just do what you think is easier for you. If you decide on the driver side. Its not as tight as you would think, since you will have all the panels off anyways.

You probably know this, but make sure you have a fuse in your cable no more than 18" away from the battery.

Thanks for the help. I suspect my curiosity will get the best of me and I'll try to go thru the passenger side. But if that fails I feel like I have a backup plan.

 

[chillaxing]

No prob, but I have a favor to ask. Can you post a pic if you decide to go through the passenger side? I might run another amp that needs its own 1/0 run, and there is noway i'm gonna try to make it fit through the same gromet. thanks

 

[having fun]

Cut the nipple and push your wire through. Reach up there from the inside, you will feel your wire.

I have a 8 and 12 gauge in mine, I even heated a screw driver and made another hole for a 4 gauge wire.

 

[eds72]

No prob, but I have a favor to ask. Can you post a pic if you decide to go through the passenger side? I might run another amp that needs its own 1/0 run, and there is noway i'm gonna try to make it fit through the same gromet. thanks

Absolutely.

I know myself too well. I got restless a bit ago and poked a little hole in that grommet. I pushed a small wooden stick about 8-10" into the hole, then went to the passenger compartment to find it. It must be my lucky day because I could see it right there just to the right of the the opening where the glovebox goes (I took it out).

I'll snap some pictures and hopefully post them a bit later.

 

[eds72]

Cut the nipple and push your wire through. Reach up there from the inside, you will feel your wire.

I have a 8 and 12 gauge in mine, I even heated a screw driver and made another hole for a 4 gauge wire.

Yep, thanks. I got brave (or stupid) before your post and gave it a shot. Very simple.

 

[having fun]

Yep, thanks. I got brave (or stupid) before your post and gave it a shot. Very simple.

Cool, go ahead and get braver and make another hole now. LOL

I crawled up there when I did mine the first time, age and not so flexible didn't help either.

 

[eds72]

Pictures

These pretty much say it all....

 

[boondoggle]

Any chance yoou could re-post those pics?

I'm wanting to run a wire for a Transmission Temp Fluid gauge (so will probably want it on the drivers side) but if the passenger side grommet is similiar looking it will give just a hair more confidence when I go poking through things.

Thanks!

 

[Runamok]

Yes please repost the pic thx!