Apparently The GMC Hummer EV Does Not Mix Well With Water

Electric Vehicles / 11 Comments

Owners are already reporting electrical issues.

As most of us know, electricity and water don't mix together too well. Unfortunately, somebody forgot to tell Hummer, which is kind of necessary since it's now in the business of building EVs.

In late July, General Motors issued a service bulletin (22-NA-144) for the 2022 Hummer EV. It claims owners have complained about inoperative buttons connected to the driver's front door switch bank. The controls connected to this switch bank include the power windows, door locks, and the power-adjustable side mirrors. "Some customers may also report unwanted activation of the theft alarm system or random messages on the digital instrument cluster," the service bulletin stated.

2023 GMC Hummer Driving Front Angle GMC

These problems stem from a poor A-pillar seal, which allows water to get through and mess with the switch bank. It's a quick fix and, according to GM, should take no more than 3.5 hours.

This service bulletin only mentions 2022 models, most of which are sold out. All Hummer EV Edition 1 models are spoken for, and the waiting list is currently 17 years long. To be clear, you won't have to wait that long for the new 9,000-pound electric truck, but Hummer is struggling to get production up to speed. In early July, it was reported that GMC was only producing 12 cars per day, which is way off its target. The good thing about this slow production rate is that Hummer still has time to fix its obviously substandard door seals.

2022 GMC Hummer Side View GMC

The second electrical issue is more concerning, but since GM released the information as part of a Customer Satisfaction Program, it's not worth storming the Hummer factory in Michigan with pitchforks yet.

GM is conducting field investigations for the 2022 Hummer EV and the 2022 BrightDrop EV600 delivery van. According to GM's document, "certain 2022 model year GMC Hummer EV and BrightDrop EV600 vehicles may have a condition in which the high voltage connector may corrode and allow water to leak into the high voltage battery. A Malfunction Indicator Light (MIL) may illuminate if this issue occurs."

The issue has nothing to do with the battery, in case anyone wants to make an unwarranted Chevy Bolt reference.

2023 GMC Hummer Front View CarBuzz 2023 GMC Hummer Front-End View CarBuzz 2023 GMC Hummer Rear Angle View CarBuzz
2023 GMC Hummer Front View
2023 GMC Hummer Front-End View
2023 GMC Hummer Rear Angle View

The fix is even easier than the malfunctioning switch bank. It involves using compressed air to clean the electrical connector areas and cleaning them with 3-M High Power Brake Cleaner. After disconnecting the five HV headers with a general-purpose body solvent, they need to be reconnected and sealed with RTV Engine Sealant.

There are only about 424 vehicles involved in this field inspection, and the split between the Hummer and the BrightDrop is unknown. Once again, at least GM knows and has time to fix the issue before Hummer production hits full capacity. Still, one has to wonder whether there should have been a problem in the first place, considering that an off-roader will likely encounter water at some point in its life, EV makers should therefore ensure there's no possible way water can get into the battery pack.


Rivian did a fantastic job making the R1T's battery pack as waterproof as possible. An R1T owner recently showed off by launching a boat from the shore. Believe it or not, the Tesla Model 3 also has an impressive wading depth.

It's one of the many reasons why we believe the future of off-roading is electric. Apart from the instant torque, you don't have to worry about water getting into essential components. With water being electricity's ultimate nemesis, we expected a much higher standard from EV makers.

Hummer did not get to that standard, but it caught the problem early enough to rectify it.

Mark Reuss/LinkedIn

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