The problem apparently stems from an unknown quality issue that GM refuses to specifically state. A company spokesperson did acknowledge that the automaker “has notified Chevrolet and GMC dealerships to stop the delivery of certain 2021 [Silverado HD and Sierra HD truck]. We are investigating a potential quality issue with these vehicles. We have no additional information to share at this time.”
However, a GMC dealership employee claims they know the reason why: a wire chafing problem that could be a fire hazard. Again, this is unconfirmed so until GM does so otherwise it remains pure speculation. We don’t think owners should be alarmed at this time. The situation isn’t a good one for dealerships.