General Motors is recalling more than 323,000 heavy-duty pickup trucks in the U.S. because the electronic tailgate release switches can short circuit and open the gates while the vehicles are in park.

The recall covers certain Chevrolet Silverado and GMC Sierra 2500 and 3500 trucks from the 2020 through 2024 model years.

The National Highway Traffic Safety Administration says in documents posted on its website Tuesday that water can get into the switches and cause the tailgates to open when in park gear. The agency says that can result in unsecured cargo falling out of the beds, creating a road hazard and increasing the risk of a crash.

GM is advising owners to check that the tailgate is closed and latched before they drive the trucks. Dealers will replace an exterior touchpad switch. Owners are to be notified by letter starting March 18.

GM dealers also have been told to stop selling affected vehicles until repairs are made.

The company says in documents that it has 136 complaints about the tailgates opening unexpectedly. GM reported one complaint of a minor injury and three complaints of minor property damage.