PunchOut location?

firefighteremt3100 · March 31, 2006

A friend told me there is like a 1" punchout in the firewall that you can punch out and put a grommet in to run wires through. Can anyone tell me or take a picture of where exactly it is on a 2004 Silverado? I've looked but I can't seem to find it. Thanks.

MS3DALE · March 31, 2006

The "NBS" trucks with the snow plow prep pkg. (RPO Code VYU) used to have an emtpy grommet (located around the area under the brake master cylinder) that can be used to run wires through.

I went out and looked at some new '06's on the lot with the snow plow prep pkg. but the ones I looked at didn't have the grommet,GM must have stopped putting them in.

There are a couple other grommets on all trucks that are already used by the factory that you could use to run wires through.

resqguy · March 31, 2006

There should be a little punch mark on the engine side of the firewall just below and towards the drivers side of the brake booster. You need to pull back the insulation to see it. On the inside, there is a circular cutout on the rubber firewall cover that you need to open. You should then see the other side of the punch mark. I drilled a 3/4" hole from the outside using the punch mark as start, and inserted a nice rubber grommet to feed wires thru.

MS3DALE · March 31, 2006

There should be a little punch mark on the engine side of the firewall just below and towards the drivers side of the brake booster. You need to pull back the insulation to see it. On the inside, there is a circular cutout on the rubber firewall cover that you need to open. You should then see the other side of the punch mark. I drilled a 3/4" hole from the outside using the punch mark as start, and inserted a nice rubber grommet to feed wires thru.

Thats probably the punch mark that the factory uses to drill out the hole,Thats the location where they put the factory grommet.

firefighteremt3100 · March 31, 2006

There should be a little punch mark on the engine side of the firewall just below and towards the drivers side of the brake booster. You need to pull back the insulation to see it. On the inside, there is a circular cutout on the rubber firewall cover that you need to open. You should then see the other side of the punch mark. I drilled a 3/4" hole from the outside using the punch mark as start, and inserted a nice rubber grommet to feed wires thru.

<{POST_SNAPBACK}>

Thanks I will check it out. I made the mistake of running wires through the grommet/rubber tube that takes the wiring to the door and got sidetracked and forgot to silicon the little hole i made. Water got inside my truck and damaged some connecters.... Guess I learned the hard way. Just seems like no easy way to pass wires through the fire wall. I will have to go check out where you guys are talking about soon as it stops raining. Thanks again.

sonjaab · April 1, 2006

YO RICH !!!!!!!!!!!!!!!!!! HEY !

Hey Fire.........check out this link with pics on where to drill the hole !

Gm quit drilling it in 04.

Me and the snowplow guys have done it several times...........

http://www.plowsite.com/showthread.php?t=1...t=hole+firewall

The second pic. is the best one

.............................geo

firefighteremt3100 · April 1, 2006

YO RICH !!!!!!!!!!!!!!!!!! HEY !

Hey Fire.........check out this link with pics on where to drill the hole !

Gm quit drilling it in 04.

Me and the snowplow guys have done it several times...........

http://www.plowsite.com/showthread.php?t=1...t=hole+firewall

The second pic. is the best one

.............................geo

<{POST_SNAPBACK}>

Thanks sonjaab,

I checked it out and it helps somewhat. I will have to see if I can find it tomorrow when I pull up the carpeting to make sure everything is dried out underneath. Once again this board proves more useful then the local idiots...er I mean dealers ;)

MS3DALE · April 1, 2006

YO RICH !!!!!!!!!!!!!!!!!! HEY !

Hey Fire.........check out this link with pics on where to drill the hole !

Gm quit drilling it in 04.

Me and the snowplow guys have done it several times...........

http://www.plowsite.com/showthread.php?t=1...t=hole+firewall

The second pic. is the best one

.............................geo

Hey sonjaab,Hows it goin'?

That makes sense that GM quit drilling the hole in '04 because I went out and looked at our '04 2500HD PartsTruck that has the "VYU" snow-plow prep pkg. and I noticed that when they mounted our Meyer snow plow they used an existing grommet to run the wires through,I never noticed that before,but then again I never looked how they ran the wires until this issue came up.

The funny thing is that GM still lists the 1.65" (42mm) grommet as coming with the "VYU" pkg. in the '06 truck order guide,Guys have got to be shaking their heads trying to find it when its not there!

I kinda' think it was stupid of GM to stop drilling it out,It sure was nice it was there if you needed it,Wonder what their reason was to stop drilling it?

sonjaab · April 1, 2006

FIRE.............That 2nd pic (with the red circle) is the best place to

drill. There is already a dimple there to guide your drill not to

mention its the EASIEST place to get a drill into !

A few guys have tried the area where the clutch and slave would

go. There is even a cut out in the insulation pad but its a BIG

PIA to get the drill in there !!!!!!!!!!!!!!!!!!!!!!

sonjaab · April 1, 2006

RICH.........How about trying to find the wires for the roof beacon

light on the VYU plow prep.? They are always deadheaded in the

headliner over the driver. We just pull the headliner down GENTLY

and fish them out. Sometimes we pull off the plastic piece in the left

rear B pillar. Thats where the relay is in the reg. and x-cabs. The

wires run bottom to top anyhoo then lead the wires out the 3rd eye

brake light ! The crew cabs have the wires and relays run up the

pillar between the front and rear left doors....FYI !!!!

But most folks and dealers don't know that

you have to install a maxi fuse in the stud #2 slot under the hood

to power it up (years 03 and up)!!!!!!!!!!!!!!!!!!!........geo

firefighteremt3100 · April 5, 2006

Ok. I finally did it. I got gutsy and drilled through the firewall. Everything went great. I dont have a place to host pictures right now so I cant post it. But if you want pics, send me a private msg and I can email. Thanks again for all the suggestions and help.

-Brian