GMC Hummer EV owners aren’t choosing it because it’s the best truck or EV on the market. They’re buying it for the fun factor. But that fun quickly fades when the vehicle doesn’t work properly. That’s where the manufacturer’s warranty is supposed to step in—and for a while, it did, covering Dustan Broom and his SoFlo Customs-modified electric Hummer. But then GM pulled the plug and canceled his warranty altogether.

More: GM Voids Warranty On Custom SoFlo GMC Hummer EV

After our initial coverage, Carscoops obtained documents from the owner showing that GM had actually honored the warranty for some time, even with SoFlo’s modifications. So what changed? Many questions still remain.

A Rough Start with Recurring Issues

Broom picked up his Hummer EV from SoFlo in April of last year. Almost immediately, he had issues with the My Modes settings and with the power tonneau cover. Hoping to sort that out, he took the pickup to the dealer for service. On his first visit in July, employees documented in his paperwork that they ordered new parts to fix his tonneau cover. However, they claimed they couldn’t replicate the issues with My Modes. So Broom waited. And waited.

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Months went by according to Broom and then finally, in December, his MyModes replacement component arrived at the dealer. As part of the job, the service team said they’d need the truck for a few weeks as the high-voltage battery had to come out. When Dustan picked up his truck, “Nothing was fixed,” he tells Carscoops. In fact, he claims the My Modes functionality, which would occasionally work before, has been dead ever since this incident.

A Smoldering Problem

However, even if the suspension modes weren’t working, Broom was also supposed to have his power tonneau cover fixed. That issue wasn’t unique to him either. It was part of a service update “N232434060”, which includes swapping out the power tonneau cover motor as needed. Less than a month after the truck left the shop, things reportedly went from bad to smoky.

Broom reports that on December 5, his cover malfunctioned and made a loud popping sound. After going inside to research how he might remedy the issue, he came back out to find the cover smoking while the GMC sat in his garage. “I flipped out. Called a few dealerships no one was of help, one told me to drive it into the road so I didn’t burn my house down. I was able to unlock the cover, setting the top piece free which, thankfully seemed to stop the burning,” he says.

Less than two months later, Broom returned to the dealership to finally have the tonneau cover repaired under the same service update. Apparently, the necessary parts hadn’t been ordered back in July as originally promised, only after the near-fire incident. Ten days after dropping off the Hummer EV for the repair, Broom got a call that would kick off this entire ordeal.

Warranty Revoked—With No Explanation

According to Broom, the service manager informed him that while his tonneau cover had been fixed, GM had decided to void his entire vehicle warranty due to the modifications done by SoFlo Customs.

More: GM Penalizes Corvette, Hummer, And Escalade V Flippers By Cancelling Warranty

“I was told today GM did NOT perform any technical analysis of the truck, they STILL do not know what the problem is but claim because my truck ‘looks’ the way it does the entire warranty is void and they refuse to fix the service light issues and the My Modes issues, not to mention the lost value of the truck having a 100% voided warranty,” he says.

Documents shared with Carscoops indicate that GM specifically voided the warranty because it blames SoFlo for the My Modes issues. Across several work order items, the dealer writes “NO WORK DONE NEEDS TO GO BACK TO THE SHOP WHERE MODIFICATIONS WERE DONE.” That said, we’ve reached out to SoFlo several times and haven’t received any response. The same is true of General Motors who seemingly approved warranty work and then changed its mind after doing it for some time on this Hummer EV.

What’s Behind the Warranty Cancellation?

It’s possible that GM has a valid reason for the denial, but the lack of transparency makes it difficult to say for sure. Did the modifications contribute to the issue in question, or is GM applying its policy inconsistently? That’s the real debate here.

The Wrinkles Abound

There are two key aspects of this story that still leave lingering questions. First, Broom tells Carscoops that the service manager attributed the warranty cancellation to his bent ride height connecting rods. These aftermarket rods allow for adjustment of the factory ride height but do not alter the core functionality of the air ride system. One online retailer describes them as a simple modification that retains factory performance while enabling slight height adjustments.

Beyond that, Broom has other concerns. He suspects GM may be using the modifications as a convenient excuse to sidestep corporate liability. Specifically, he wonders if the tonneau fire is playing a larger role in this situation than the modifications themselves, with GM leveraging the aftermarket work as justification to deny coverage and avoid potential legal complications. Without responses from either GM or SoFlo, the situation remains murky, leaving only customer testimony and dealer documentation to piece together the puzzle.

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Perhaps the biggest takeaway is that buyers of modified vehicles, especially high-tech EVs, should tread carefully. Factory warranties can be a gray area when aftermarket work is involved, and as this case shows, what’s covered today might not be tomorrow if someone other than an authorized dealer gets their hands on the vehicle.

Image Credits: Dustan Broom, Suspension Superstore, SoFlo Customs

Dustin Broom says that after suffering a heart attack in April 2024, his outlook on life changed. He decided to trade in his Dodge Hellcat and Audi R8 for the custom GMC Hummer EV you see here—modified by the folks at SoFlo Customs. The truck, he tells Carscoops, “checked all the boxes.” But now, less than a year later, his local dealer has voided his warranty, citing the modifications.

Shortly after purchasing the truck from SoFlo customs, Broom took the SUV to his local dealer for work on the MyMode switch. In addition, his service light has been “always on” he says and as a result, he can’t raise or lower the vehicle. Despite that, features like Crab Walk and 4-Wheel Steering continued to work as expected. Evidently, the dealer has tried to fix these issues since May of 2024.

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According to Broom, the GM dealer initially told him the problem was related to a faulty module that needed repair. For whatever reason, something then changed at the dealership. On February 7 of this year, Broom posted in a Hummer EV Facebook group about the development, revealing that GM had refused to honor his warranty.

“Well, guess I get to start litigation with GM. GM service district manager said due to the nature of the upgrades done to my truck (FYI they put bigger tires on it, and painted it, and put different leather interior) my warranty is now completely void. I am never buying a GM product again,” he says.

It’s worth noting that Broom says SoFlo told him the modifications wouldn’t void the factory warranty. However, he says GM didn’t just deny coverage on certain components, it voided the entire vehicle’s warranty.

Was the Warranty Voided Due to Ownership Transfer?

Another wrinkle in the situation is that Broom purchased the truck used, so it’s unclear whether GM intended to cancel the warranty due to the ownership transfer or if something else is at play. In any case, the question remains: Who is to blame here? Should GM honor the warranty if the modifications are purely cosmetic?

More: Warranty-Denied Elantra N Owner May Have Admitted Modding His Car Online Too

Under the Magnuson-Moss Warranty Act, manufacturers cannot void a vehicle’s warranty simply because of aftermarket modifications, unless they can prove those modifications directly caused the issue. Carscoops reached out to both GM, the dealer in question, and to SoFlo customs for more insight on the situation. As of this writing, neither GM nor SoFlo Customs has responded to our request.

The dealership, however, did provide a statement:

“We as a dealership have nothing to do with a warranty being blocked. That comes from higher up in the manufacture. They hold the warranty on the vehicle and that is their decision, we as a dealership have to follow what they tell us to do as they hold the warranty.”

What do you think? Should GM honor the warranty, or is the company within its rights to deny coverage? Let us know your thoughts in the comments below.