General Motors is recalling almost 820,000 pickup trucks because of a glitch that could cause the tailgate to open unexpectedly. 

The electronic latch mechanism used to open the gate of certain 2020-2024 Chevy Silverado and GMC Sierra truck beds could short circuit if water enters the tailgate, leading to the gate opening, the automaker said. That could allow objects in the bed to fall out.

GM has received 136 complaints of tailgates opening while vehicles were being driven, according to a report posted on the National Highway Traffic Safety Administration's website. But the gate can only open when the vehicle is in park, which means drivers are hitting the road without realizing what had occurred, the automaker concluded. 

The complaints included one allegation of minor injury and three involving minor property damage, GM said.

Owners are advised to manually close their tailgate before driving until the recall is finished. GM will start notifying owners if their car is subject to recall on March 18, with dealers then replacing the exterior switch that operates the tailgate with more water-resistant material, the automaker said. 

The recall includes more than 570,000 vehicles sold in the U.S. and another roughly 249,000 in Canada. 

In:
• GM
• Product Recall
• Chevrolet
• Auto Industry
• National Highway Traffic Safety Administration

Kate Gibson

Kate Gibson is a reporter for CBS MoneyWatch in New York.