2024 2024 Silverado 1500 Amp/Sub Power Wire Install w/ Firewall Update

Chevyspeedster · Sunday at 06:46 AM

Hey all, first post and hoping this can help out.

As many of you know and or finding out, the 24's and up are apparently a new style Firewall Grommet system leading into the truck from behind the battery. But not to worry, this will hopefully be the clearest new how to so far without a youtuber making a video of this.

The truck now, instead of having a nipple coming from the firewall grommet on the engine bay side, is now a plastic bezel. The nipple can be located from under the dash still, however, and is still just as easy as an install as before.

Pic 1 is from the engine bay. You can see the channel where the wire will exit/enter the truck.

Pic 2 is from inside the truck and what is looks like if you peel the grommet back, which does not need to be done because then you'll need to replace the rubber around the grommet to around the plastic shroud which is not the easiest thing to do.

Just use an exacto #1 and cut a plus from the inside of the truck in the nipple. Pic one shows where the wire will exit.

Pic 3 shows a 4ga wire in it. It fits 4ga wire really well. No sure about 2 or 0... you may have to trim the nipple off then just make the plus/X cut bigger.

I also did not need to remove the battery to do any of this. Just work from mid engine with a ladder/step stool. Not the side of the truck.

Step 1.

Take out the multifunction power supply converter box and bracket that is located behind the glove box and bolted to the kick panel right underneath the firewall grommet.

The two tabs holding this box in need to be pulled towards you (the rear of the truck) and slid up. They will be blocked by the A/C fan I believe it is, but nevertheless cannot be pulled all the way up enough.

Carefully pull it out. You'll have to finagle it a bit, but the box will come out. This is the only way to access the second 10mm nut that's on the stud holding the bracket in place.

You do not need to remove the wire harness. I didn't.

Remove both 10mm nuts with an extended socket.

Step 2.

I used an exacto like #1 blade and sliced a plus sign in the power wire pass through nipple.

Step 3.

Electrical tape a long zip tie to the wire.

Use a little soapy water or some lubricant (I used just a little petroleum jelly) to slide the power wire through the hole. I went from the inside of the truck and pushed it to the outside (inside the engine bay).

Continue install as you would with all the other older amp/power wire install guides out there.

...Special Notes...

You may need to remove the plastic cover kickplate that is plastic welded to the floorboard part of the carpet placeholder cover.

I did this by removing the fuse box cover plate then removing the 8mm screws. This allows you to pull the panel backwards and pop out the kickplate. The floorboard part must be pulled upwards. Do not try to separate these two pieces at the seam! They are plastic welded together.

For another good run through check out here:

https://www.trailboss.org/threads/firewall-grommet-change-in-the-2024-lt-trail-boss-for-power-wire.2109/

Hope my photos are more helpful.

Edited Monday at 06:44 PM by Chevyspeedster
Added note

Chevyspeedster · Sunday at 07:02 AM

Here's some more photos showing the tray that need to be removed.

Edited Monday at 06:36 PM by Chevyspeedster

Chevyspeedster · Sunday at 07:03 AM

Edited Monday at 06:36 PM by Chevyspeedster

Chevyspeedster · Monday at 06:14 PM

Update on the build.

I removed the fuse block (bus bar) above the battery from the truck.

Also dremeled out the channel in the plastic to run a KnuKonceptz 4/8 Gauge in Line Mini - ANL fuse holder. I specifically chose to go with this fuse holder because of the way the fuse blocks are made. The metal is carved out at a 90° and drops the fuse down into the block instead of other designs remaining a larger higher mounted fuse. There's also an angle to it, instead of being mounted flat.

I really wanted to go with an automotive inline breaker but couldn't think of a way to mount it nicely and it would most likely take up too much room in the trucks fuse block and I didn't want to dremel the whole thing out. I feel like the amount I demeled was enough, and IMO it will looks nice.

I then drilled a 9/64's hole in the base of where the screws are in the KnuKonceptz block and the screw caps just popped out. Then disassembled the fuse holder.

The 9/64's holes are a perfect size for the screws to mount in the trucks fuse block channel. The trucks fuse block is made out of a plastic that you can thread these screws into and they then will tightly be held in place to then screw in the KnuKonceptz fuse holder blocks. This will also act as a thread lock tight somewhat and help captive the screws from backing out in the future. (that's the hope anyway)

Edited Monday at 06:36 PM by Chevyspeedster

Chevyspeedster · Monday at 06:17 PM

You can see what the screws look like from underneath and they will be out of the way from interfering with anything. It's just the plastic covering of the battery down there.

The box closes nicely and should be a very tighty install.

Edited Monday at 06:37 PM by Chevyspeedster

Chevyspeedster · Monday at 10:34 PM

Last few pictures should do it with the actual wire ran through. I'll post maybe one or two more when it's all tidied up.

Edited Monday at 10:35 PM by Chevyspeedster

Chevyspeedster · Tuesday at 12:36 AM

Here's the almost finished shots. It of course got too dark but tomorrow I'll install the crimp sleeves and everything else to clean it up for a nice install.

Cheers all

Edited Tuesday at 12:45 AM by Chevyspeedster

Chevyspeedster · Tuesday at 12:37 AM

More finished shots.

On the last picture you can see the wire looped a little high. That will be adjusted tomorrow when I get some sunlight to work and install the crimp sleeves. But I wanted to make sure I had plenty of wire. The end result will look nice like it it stock. I like the clean looks and not the aftermarket wires all over the place.

Hope you've learned something and enjoyed

Edited Tuesday at 12:50 AM by Chevyspeedster

kickass audio · Tuesday at 02:22 AM

very nice work and clean install! I am running the factory bose radio and it's good enough to not bother with aftermarket speakers but I did replace the useless speakers in the rear door with the leftover 6.75" speakers I had from my 2014 silverado. I ran a similar path on the fuse panel for my 1/0 gauge wire that feeds from my 370A mechman alternator but I didn't fuse it and I added the 1/0 gauge ground wire from the alternator to my negative battery load sensor at the battery and it works fine. The voltage initially would fluctuate since this alternator can work at a higher rate to recover the voltage so initially my voltage would bounce up and down a ton but it's since stabilized and rarely goes to float at 12.5v of power.

My only mistake is I accidentally snapped one of the little retaining tabs that holds the battery fuse panel cover down but it works fine and if worse comes to worse i'll look at a new cover from a junkyard or something but it's not a concern at all for me.