2024 Sierra AT4 3.0 Build

Tennpenn83 · 2026-07-13T17:23:48-0500

I am honestly a bit surprised at the lack of threads in this section. This is an absolutely perfect way to document what you have done so far and bounce ideas off others for future modifications.

I bought the truck last year but haven't really had a chance to start really building and modifying until recently. I will document here what all I have done. I will attempt to post relevant pictures as I go.

2024 GMC Sierra 1500 AT4
3.0L LZ0 Duramax
First things first, as I mentioned in my original intro thread, the truck did not come with the High Clearance side steps that it was supposed to have on its build sheet. My wife is barely 5' tall so I needed these more than anything else. Temporary solution pictured, then the side steps installed.

These may be later changed out for rock sliders with a kickout, such as these from Baseline Overland :
https://baselineoverland.com/products/2019-chevy-silverado-gmc-sierra-1500-rock-sliders-side-steps

Next, I feel that no matter what you have done to the truck, it is important to be aware of as much information as possible to maintain the reliability and longevity of the truck.

Since I had GM Accessories credits, I bought the bedside Molle panels kit. I know there are other options for cheaper kits that cover more of the bedsides, but I also had other plans for that space.

Also mounted on these Molle panels is a small shovel, axe, hatchet, fire extinguisher and IFAK. These are now under a Pace Edwards Ultragroove retractable tonneau cover with T-slot rails.

Inside the cabin I have a center console safe with 3D printed mini storage side pieces from Etsy.
https://www.etsy.com/listing/1889767577/3d-printed-truck-console-storage-bins?ref=yr_purchases

Under the driver seat, I have installed a "Sportsman Bundle" from Desert Does It.
https://desertdoesit.com/collection...lti-mount-panel-2019-2024-gm-sportsman-bundle
This holds a mini fire extinguisher, band-aid pouch, and side mount for, you know, whatever.

For my local group, a GMRS radio is a must, and I wanted something mobile. I installed a Midland MXT575 hardwired into the truck. For the antenna, I routed it through to the driver side fender and placed it on SDHQ ditch light mount on an extension, with eventual future plans for lighting.
https://sdhqoffroad.com/products/19...llar-light-mounts?_pos=2&_fid=e76b58c18&_ss=c
Speaking of lighting, I ordered a pair of Morimoto 4banger HXB lights, and a set of lenses to change from white to amber if needed. Here is a picture of those lights installed, and the Midland ghost antenna visible to the outside of the driver side light.

I then wanted to install a set of chase lights, so I found a bracket from Range Industries that bolts to the rear lower fascia and hugs close to the trailer hitch receiver.
https://range-industries.com/products/2019-silverado-rear-facing-light-mount
Installed on this bracket are Morimoto NCS 2banger lights in amber. These don't need to be super bright, like the HXB front lights. I'm not trying to blind anybody who might be behind me on the trail.

As I am only allowed to attach 10 files, I will reserve post #2 of this thread for the electrical setup.

Tennpenn83 · 2026-07-13T17:24:07-0500

To power these lights and future accessories, I installed a Garmin PowerSwitch under the hood. This has six outputs, but more importantly, 2 control inputs, is bluetooth and works with Android Auto so it comes up on the factory touchscreen. How I plan to install this is complicated, a bit harder than others, but it will look near-factory when I am done.
For electrical, the Garmin is only part of the system. I have also installed the GM Upfitter switch kit from 404 parts. Everything is installed right now except the switch panel itself - but only because I have to come up with the courage to cut into the truck, and I am procrastinating. I am planning on placing this switch panel overhead, right above the sunroof switch console. The layout for this system is as follows :
GM Upfitter switch #1 to Garmin Control input #1 - the Garmin will turn on all forward facing lights, such as the ditch lights, light bar and anything else.
GM Upfitter switch #2 to Garmin Control input #2 - the Garmin will turn on rear chase lights in a strobe pattern controlled by the Garmin.
GM Upfitter switch #3 & #4 TBD
GM Upfitter switch #5 - to a relay for the 50W GMRS radio

Garmin output #1 - ditch lights
Garmin output #2 - light bar (eventually)
Garmin output #3 - chase lights
Garmin output #4-6 - TBD

The Garmin PowerSwitch itself is mounted on another bracket by SDHQ, and I only had to drill one extra hole on the bracket since it is made for a different unit :
https://sdhqoffroad.com/products/19-current-chevy-gmc-1500-switch-pros-power-module-mount

Since the GM Upfitter kit comes with fuses and the bridge for a clean install under the factory fuse block, this is a perfect run for the Garmin.

In this picture, the wiring is a mess, but I have since cleaned it up. The red 4AWG power lead to the Garmin is now only about 8 inches long. the Garmin ground goes to the factory ground, and all the other grounds are going to the bus bar, pictured just below the factory ground and on a 6" black insulated ground wire. As I also have the PPE catch can setup, the bus bar sits cleanly on the bracket that is already there.

That's about it for now. I did not mention, but the GMRS radio mic is on a Course Motorsports phone mount, and there are not really any other interior modifications. I did also do the VSE LZ0 fuel filter setup, as well as the PPE rear differential cover. I have a PPE transmission pan and engine oil pan sitting in the garage waiting to go in. Future mods are more for longevity and efficiency than anything else. I plan to do the PPE transmission cooler and also their intercooler upgrades, as well as a Titan long range fuel tank and AEV skid plates. There are no solid plans yet for any bumpers, but I do intend on getting a winch bumper at some point.

It is my opinion to build the vehicle for what you want, and what you intend to do with it. I daily this truck, so reliability is first and foremost, but I am also planning on some long road trips and tow a mini teardrop camper frequently. Putting modifications on here that are not only useful, but also tasteful are my biggest priorities. For the future, I am open to opinions on the mods I have already done and am planning to do, but also open to ideas on bed rack, lighting, potential compressor setup, etc. Please let me know what you think.