2021 GMC Sierra 3500 Problems and Top Complaints – Is Your Car A Lemon?

Electrical system and fuel system issues among the top complaints received by the NHTSA from vehicle owners

Updated on Author: Brian Jones

Driving a heavy-duty pickup truck doesn’t just make the occupants feel like a boss, but it helps get the toughest jobs done. The 2021 GMC Sierra 3500 is hailed as a “powerful innovation” from the manufacturer, but current owners can’t agree. In fact, there are complaints swirling around the Internet about the defective fuel system and malfunctioning electrical system.

Click on other model year to view more problems: 2018   2020   2022

Problems with the Fuel System

A well-working fuel system is essential to keep the engine running as it should. However, there have been problems with the 2021 GMC Sierra 3500’s fuel system.

One Cars.com review states, “I had trouble with #4 injector…dealership replaced it.”

For the price, there should be nothing even remotely defective in these 2021 GMC Sierra 3500 trucks. Yet, this isn’t the only system that is completely failing. In fact, there’s a recall on the seat belts. That’s right – the basic seat belt wasn’t even built correctly. Over 624,000 vehicles, including this truck were recalled because the wrong seatbelt bracket was used in the front. Without this bracket in place, the front occupant could remain unrestrained during a collision, allowing them to go flying through the windshield. GMC claims to use “powerful innovations” with this truck, but didn’t get the seat belts right? It’s no wonder that the sophisticated fuel system isn’t working right. GMC is too focused on using human crash test dummies to try out the truck lineup.

2021 GMC Sierra 3500 Complaint Summary

Complaint CategoryNumber of Complaints
Power Train
Service Brakes
Fuel/propulsion System
Electrical System

Electrical System Problems

With a well-running electrical system, a smooth ride is guaranteed. Therefore, the opposite can be said when it is glitchy and defective.

The same Cars.com review also says, “Now my AC doesn’t work all the time. Although it sounds like it’s blowing it isn’t.”

Aside from having a poorly-created climate control system, it turns out that GMC got caught using defective infotainment units in some trucks as well. While the 2021 model isn’t included in the class-action lawsuits yet, it may be in the near future. In other trucks, GMC uses systems that automatically turn the volume on full-blast, even without user input. It’s as if the truck is saying, “Can You Hear Me Now?”

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Think you have a lemon? Sit back and let the experts work out your lemon case at no cost to you. The law makes GMC pay legal fees. You may be able to get your lemon out of your life. Every year, auto manufacturers buy back, replace or pay cash settlements to thousands of ‘lemon’ owners like you.

Brian Jones

About the Author:

Brian Jones spent more than 30 years working as an ASE Certified Master Tech and Parts Specialist at multiple dealerships. Brian has become an authority in the industry, traveling across the country to consult for car dealerships and contributing his expertise as a writer for several major automotive publications. In his spare time, Brian enjoys working on pickup trucks, muscle cars, Jeeps and anything related to motorsports.

See more posts from Brian Jones

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