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Running wires through the firewall...

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Old Mar 27, 2005 | 05:35 PM
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Default Running wires through the firewall...

The more mods I install the more holes I end up having to drill through my firewall to pass through a few wires at a time. It's getting rather annoying and my firewall is turning into swiss cheese. Was wondering if anyone around here know of any kind of pass-thru type terminal that I can cut a hole in the firewall and mount it so all I have to do is plug the wires into it on either side to make the connections. I have searched all over the place and can't find anything. Thanks.

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Old Mar 27, 2005 | 10:24 PM
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Usually not recommended due to the volt loss that would be associated.

It would also be difficult to connect the wires to the terminal from the out side of the car. It would be a good idea for low amperage wires.
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Old Mar 28, 2005 | 09:33 PM
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If you remove the PCM there is a large grommet behind there with only a few small wires running through it. I snipped a small hole in it, and ran my 1/0 gauge power wire through it. No need for any new holes. 1/0 gauge wire (pictured) is as big in diameter as my thumb, so there is lots of room in that grommet.

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Old Mar 28, 2005 | 10:24 PM
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Originally Posted by Snootch
If you remove the PCM there is a large grommet behind there with only a few small wires running through it. I snipped a small hole in it, and ran my 1/0 gauge power wire through it. No need for any new holes. 1/0 gauge wire (pictured) is as big in diameter as my thumb, so there is lots of room in that grommet.


Snooch. How hard was it to run that 1/0 throught the interior? I've done 2 2ga flat wire runs in my Geo to fit the wiring inside. I didn't have the room for the 1/0.

Now I haven't taken a really good look inside the camaro yet, but I'm curious.
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Old Mar 28, 2005 | 10:27 PM
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Originally Posted by Snootch
If you remove the PCM there is a large grommet behind there with only a few small wires running through it. I snipped a small hole in it, and ran my 1/0 gauge power wire through it. No need for any new holes. 1/0 gauge wire (pictured) is as big in diameter as my thumb, so there is lots of room in that grommet.
I have a truck, PCM is in a different spot, but I do have the big grommet. Mine is pretty much full.
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Old Mar 28, 2005 | 10:34 PM
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Well if that's the case you could try a junk yard and look for an Import car. They usually have molex plugs like you are describing. They would mount similary to how it fits in the door.

There is a plug that is usually on the CAR SIDE of the Door jamb side that plugs into the Molex plug that is locked into place on the DOOR SIDE of the door jamb. It would be hard to do, but you could make a templet of the area to cut out in the fire wall, Mount the molex plug so the plug end is in the engine compartment. You would be able to unplug the plug to mount a newer wire, and then clip it back in place.

Find an import car and you'll see what I mean. They range from 4 plugs to as many as 24. I would check the size of the wiring inside the plug to see what you have. Most cars come with Power windows and power door locks. On the older style systems they need larger GA wiring.

Try this out.
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Old Mar 29, 2005 | 05:21 AM
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Originally Posted by Richiec77
Snooch. How hard was it to run that 1/0 throught the interior? I've done 2 2ga flat wire runs in my Geo to fit the wiring inside. I didn't have the room for the 1/0.

Now I haven't taken a really good look inside the camaro yet, but I'm curious.
Actually wasn't that hard at all. Being that it's such a large conductor, it does leave a small lump in the carpet, but running it through the firewall was easy. The grommet is very elastic, and has foam behind it.
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Old Mar 29, 2005 | 01:06 PM
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Originally Posted by Snootch
Actually wasn't that hard at all. Being that it's such a large conductor, it does leave a small lump in the carpet, but running it through the firewall was easy. The grommet is very elastic, and has foam behind it.
Cool. Thanks for the info.
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Old Apr 3, 2005 | 06:13 PM
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PCM? Where is this under the dash?
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Old Apr 4, 2005 | 07:28 AM
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Originally Posted by Rescue Ranger
PCM? Where is this under the dash?
Attached to the firewall under the hood on the right side. It's a silver-gray box about the size of a hardcover book with a large bundle of wires coming out.
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Old Apr 24, 2005 | 11:03 AM
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anything to look out for when removing the PCM. Should you take off any "tuning" done? (Preadator, HPP, etc)
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Old Apr 24, 2005 | 03:56 PM
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No, you don't even have to unplug it to get at the grommet. Just unbolt and swing it out of the way while still attached to the harness.
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Old Apr 24, 2005 | 04:02 PM
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I had to unplug mine to get it back in. I fought that damn thing for about an hour. trying to get it lined back up and snapped into the plastic holder, clearing the wiper cowl, hood hinge etc. Finally I unplugged it and it went in much easier since it gave me a chance to move it around as i pleased.
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Old Apr 24, 2005 | 04:15 PM
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You're right, unless you pay close attention to exactly which way you turned the PCM when removing it, it can be very difficult to get it back in place. Even so, if necessary you can unplug the PCM and reinstall it without doing any special preparation such as removing programming.
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