2020 GMC Sierra 3500 Problems and Top Complaints – Is Your Car A Lemon?

Electrical system, steering and structure issues among the top complaints received by the NHTSA from vehicle owners

Updated on Author: Brian Jones

Heavy-duty trucks have a massive job to accomplish. That’s why owners opt for the capable 2020 GMC Sierra 3500. After all, the automaker labels it as “best-in-class” in many areas, so it should provide everything a consumer needs. But, it doesn’t. This HD pickup suffers from a faulty electrical system, malfunctioning steering and a poorly-built structure.

When a small malfunction happens with the electrical system, it isn’t often a big deal. After all, having an infotainment system that doesn’t play the right volume level or provides connectivity concerns is more of an annoyance. However, electrical systems can also be major, such as what’s found with the GMC Sierra 3500.

One NHTSA review states, “Progressive pause starts when starting vehicle. After a few weeks of pause starting vehicle had no power at all. Towed it to dealer they replaced a bad battery. Pause start continued and after 4-5 weeks vehicle would not start. Couldn’t turn park brake off. There was power (lights in dash came one) but didn’t start. Vehicle parked and only after sitting unused this happened both times. (1st time no start, hadn’t driven for 3 days, end of summer weather)(2nd no start, sat overnight cool weather, but no freezing). Towed to dealer and they found nothing wrong.”

Electrical system problems continue to infiltrate the GMC Sierra truck. Just look at Service Bulletin #PIT5756. This states that electrical center bolts under the hood might be loose which leads to a no crank situation, trouble starting, grinding during starting, flickering headlights, flashing headlights and unregulated system voltage. Some issues can even be linked with unexpected powertrain movement, affecting acceleration and braking. What might seem like a small problem, just a loose bolt, turns into massive issues that can lead to an accident. In this case, GMC can only claim to be the best-in-class at failing.

Click on other model year to view more problems: 2018   2021   2022

Problems with the Steering

Steering the GMC Sierra 3500 is one of the most critical aspects, especially when towing or carrying cargo. Yet, this critical system is showing itself defective. 

Here is another NHTSA complaint. “Vehicle exhibits steering wheel shake/shimmy at speeds above 50 mph, sometimes severe. Repeated attempts at repair (currently 4 dealer visits), including application of Service Bulletin #19-NA-240 does not correct the problem. GM has now indicated this is a ‘normal’ condition and will not authorize further warranty reimbursable labor for correction to dealer. This steering condition affects safety as it occurs in varying severity and with no warning, especially during driving over rough pavement/bumps, and has nearly lead to a loss of control of the truck. This condition was present at delivery of truck at 221 miles. Truck current has 1688 miles.”

There’s nothing scarier than having steering issues while towing or hauling goods. If someone were to lose control of the Sierra 3500, there are further safety issues to be aware of. NHTSA Campaign Number 20V446000 is an air bag recall that states the Roof-Rail Air Bag (RRAB) inflator contains a diffuser component that wasn’t properly crimped, causing it to separate from the air bag. What owners are left with is an air bag that might not deploy as intended, especially if the truck rolls because of steering issues. Before driving this GMC truck, it might help to exercise arm muscles in order to put the effort forth it requires to keep the pickup on the road.

2020 GMC Sierra 3500 Complaint Summary

Complaint CategoryNumber of Complaints
Electrical System
Power Train
Service Brakes
Unknown Or Other
Air Bags
Electrical System:12v/24v/48v Battery
Forward Collision Avoidance: Automatic Emergency Braking

Structural Problems

The GMC 3500 costs far more than the standard truck lineup and it is designed for bigger jobs, so it should be made to handle the work, but it’s not.

Here is one more NHTSA complaint. “While towing a fifth wheel camper, the exhaust was so hot it melted the camper directly behind it. Was caught in side mirror before anything caught on fire.”

Showing how terrible this structure and design is, you can look at two more recalls. NHTSA Campaign Number 19V814000 states that over 500,000 vehicles have carpet floor covering that could catch on fire because of the hot gas venting through an opening in the pretensioner bracket. It’s just one more way that the GMC is attempting to start on fire. But that’s not all. NHTSA Campaign Number 20V324000 says the hood-latch striker wires might not have received the appropriate level of heat treatment. Because of this defect, the striker wires could fracture, causing the hood to open unexpectedly during a drive. Imagine towing a heavy trailer when the hood suddenly opens and blocks the view. This is the time when those air bags need to be working, but they aren’t either. It seems that this GMC truck is best-in-class, of having the most defects across multiple systems.

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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
  • Maurice P

    My 2020 3500 Sierra Denali check light came on with only 6200 miles on it I’m the only owner I received a text stating it was a emissions problem so when I took it back to the dealership I was told I wasn’t driving it hard enough in my mind I’m wondering what’s next

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