Need To Drill A Hole In My Firewall.

cghbuilder86 · November 16, 2010

Okay I've been out looking over my truck really good today. I am wanting to add an amp and I need to run a wire to my battery from the inside of the cab. (I already have a post in the audio section on this but this is really more general info about the truck, plus I wanted to be sure nobody misses this).

Looking from under the hood of the truck there is a clear empty spot of metal. It seems everywhere else is taken. Not many clear places on the firewall I can find. As you can see in the pic this spot is just above and to the left of the steering column shaft.

Now, looking from the inside under the dash there is also a clear smooth spot. My question is this the same spot and is it okay and clear to drill a hole through it? From the pics inside the truck it is also just above the steering shaft and to the right. But I don't know of anyway to find out if this is the same spot inside and out. I'm thinking it is, but I figure some of you diy repair guys and mechanics would already know. Also is there anyway I could test for sure before I go drilling into it? I would die if I drilled a hole from under the hood and then looked inside and the hole wasn't there or had come out in a different spot!!

[email protected] · November 16, 2010

On my 2001 I ran my wire through the big rubber grommet that hold all those tiny wires that go to the BCM, I try to refrain from drilling new holes, if possible.

Mckenzie · November 16, 2010

my bud ran the wire through a hole to the far right(facing the motor) and it came out near to the right of the brake pedal

Now the amp is mounted behind my back seat and is screwed into the sheet metal

5829BMG · November 16, 2010

Take a punch and dent it from the outside then look at it on the inside for same dent. At least that way there's no hole. Just a thought.

dirtfan21 · November 16, 2010

On my 2001 I ran my wire through the big rubber grommet that hold all those tiny wires that go to the BCM, I try to refrain from drilling new holes, if possible.

+1 On my '95, '99, and '00 silverado's I ran the wire through the large grommet of wires from the control module/under hood fuse box into the cab. Just cut a very small splice in the rubber grommet attached to the fire wall. The splice should be smaller than the gauge of your power wire, then push the wire through. It will create its own hole size and finish it off by weather tighting it with a clear sealing compound.

I have never had a water, draft, or shorting problem doing it this way.

marine_devildog801 · November 16, 2010

On my 2001 I ran my wire through the big rubber grommet that hold all those tiny wires that go to the BCM, I try to refrain from drilling new holes, if possible.

+1

When I put my lights in I did the same thing. Just find the group of wires that go in on the driver's side through the rubber piece, poke another tiny hole, and put it through there. That way it is easy to find on the inside too.

tomr80 · November 16, 2010

On my 2001 I ran my wire through the big rubber grommet that hold all those tiny wires that go to the BCM, I try to refrain from drilling new holes, if possible.

+1

When I put my lights in I did the same thing. Just find the group of wires that go in on the driver's side through the rubber piece, poke another tiny hole, and put it through there. That way it is easy to find on the inside too.

+1 thats what i did!

Love that lightbar!!! Looks sweet

cghbuilder86 · November 17, 2010

I will probably try the punch idea tomorrow and see how that goes. But incase I'm still not sure can ya'll tell me more about where you are talking about? I have looked and looked and all the spots where wires are going through look sealed off and tight. Looks kinda like it would be a PITA to run another one. Has anybody got any pics? Or just explain really clear so I know where you are talking about?

GasHog369 · November 17, 2010

I ran all my wires thru the hole where there is a big grommet under the drivers side front floor board where your mat would be. Pop off the trim pieces and lift up the carpet partially , you will see it , then rout your wires in the frame and up into engine bay. Worked for all my wires / airlines / etc...

cgalford · November 17, 2010

Not sure about the spot you're looking at but a good spot in general is the blank space for the clutch right behind the junction box in the drivers footwell.

nickvrebel · November 17, 2010

as most have suggested, use the existing grommet

The way I accessed the one I used was to go from the inside, to the left of the brake pedal there is a junction box/ fuse panel. release it from it's clips and slide it to the side. You will see a large grommet with a large bundle of wires coming through it. to the side of the existing wires, poke a hole with a small pocket knife. Use a wire coat hanger and stab it through the hole and then use the coat hanger to pop a hole through the other side. once the hanger is through you can located it from under the hood. Now use electrical tape and tape your power wire to the hanger and pull it through the grommet. It may take some cussing and swearing, but it will come through. Tape it good so that it doesn't come off in the process. I've done three trucks this way.

cghbuilder86 · November 18, 2010

Thanks to all who have replied to this post!

Everyone seem to be saying that it would be better to go through the exstiting grommet than to drill a new hole so that is what I am planning. I did unclip the fuse pannel on the inside and I think I found the grommet you are talking about. I took some outside pics though so I could varify. I just don't want to screw anything up.

So is this the grommet in the pic that my wire should come out of?

I am still waiting on my amp and wiring kit to come in but I am going to be so ready to jump on it when it gets here.

cghbuilder86 · November 18, 2010

as most have suggested, use the existing grommet

The way I accessed the one I used was to go from the inside, to the left of the brake pedal there is a junction box/ fuse panel. release it from it's clips and slide it to the side. You will see a large grommet with a large bundle of wires coming through it. to the side of the existing wires, poke a hole with a small pocket knife. Use a wire coat hanger and stab it through the hole and then use the coat hanger to pop a hole through the other side. once the hanger is through you can located it from under the hood. Now use electrical tape and tape your power wire to the hanger and pull it through the grommet. It may take some cussing and swearing, but it will come through. Tape it good so that it doesn't come off in the process. I've done three trucks this way.

This is some good clear instruction man. Thanks I really appreciate it. It is very help for someone that has been doing a lot of research on the whole process for the last couple of weeks. I plan on doing it exactly like you have explained here.

[email protected] · November 18, 2010

Yep, Nick described it to a T. That's how I've routed wires the last three times I've installed systems.

nickvrebel · November 18, 2010

you are welcome.

the grommet in your pics is the correct one. just be sure to leave plenty of clearance between your hole and the existing wires to be sure that you don't accidentally damage the truck's harness (I usually shoot for about half way between the existing wires and the edge of the grommet). You can use a flat blade screwdriver to enlarge the hole if you get in a bind, but try your best to do it without first to keep the hole as tight as possible - this varies with your wire size too of course.

Once you have the wire pulled through you can route it under the truck's carpet and no one will be the wiser.