2014 - 2018 Silverado crew cab 1/0 cable pass through location

Madcow2020 · February 16, 2018

So I was not able to find any information on a good location to run the 1/0 AWG cable in to the cab of my truck.

So smaller power cable can be ran down the channels inside the cab of the truck and out the firewall grommet. Plenty of information out there on that.

I used a 1/0 waterproof firewall bulkhead pass through. I purchased it off of eBay. Link below:

https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F222093378939

Before removing the rear seat mark the outline of the left side rear bracket.

I removed the passenger rear seat:

4 x 18 mm nuts a ratcheting wrench and deep socket worked great.

2 x 10 mm bolts holding the smaller seat to the big seat.

Removing the two 10 mm bolts allows you to just take the small seat out.

The firewall / bulkhead pass through needs a 1” 1/8” hole. Use whatever method you want to make the hole be it a hole saw or a step bit. I used a step bit.

Hold the pass through next to the seat bracket outline. Make sure the retention nut is in so you account for the extra space. Mark the center of the pass through. Pre drill a pilot hole from the top. I used a 1/8 bit.

Use your preferred hole making device from the bottom.

Insert pass through.

I could of gone 3 hairs further right and been good. I’ll follow up after I build and run the cable under the truck. I hope this helps someone else from all of the headache I had.

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Maxsuperdog · February 18, 2018

O gauge does fit in the door channels. It requires removing all the zip ties that are factory installed. It's a tight squeeze but doable. Probably about the same amout of work that your doing.

Madcow2020 · February 19, 2018

Does it fit with the plastic channels installed?

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1SLOW1500 · March 22, 2018

I have in the past removed the channel and duck taped the wires down. Sounds bad but looks clean and protects wires. Best option is running the cable under the carpet but through the center of the truck, but that truck had sound deadening and padding. Also a good option is under the truck but I go overboard and loom it and auto motive style back tape it. The hole up though the floor should be as close to the rear wall as possible to avoid issues down the road.

there is also a Awesome stretch tape that is black self healing and water tight also good to like 800*.

If the firewall hole is not going to be uses you can always step grommet that hole so you can use it in the future..

Madcow2020 · March 27, 2018

Yea I went under the truck just couldn’t find any good information on where to drill the hole. That’s why I put this post out there for others wanting to do the same. For the cable under the truck I used the poly mesh tech flex with heat shrink at both ends and galvanized copper ends with 20 ton crimps.

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1SLOW1500 · April 18, 2018

So the Denali has a Larger HVAC unit under the passenger dash, I believe it is the blower to the AC seats. So the firewall drill hole was a no go for me.

The BEST way is the passenger a pillar boot. You can't see it and can reach it but it is HUGE. With the door sill trim removed you can see wiring and just feel your way up to the boot. I use a old metal antenna with a sharp end. Then once that is through I safety wired it to the cable and pulled it right through. It will come out behind the fender with a ton of room and nothing sharp or hot to ever hurt it.

This way is a shorter run and no over the engine bay. Water tight rubber boot and cleanest install.

Also I jammed my hands behind battery and between fender and firewall but I believe the average Joe with larger hands could remove battery to do it much easier.