The U.S. government is investigating whether General Motors should add about 312,000 vehicles to a 2015 recall for headlights that can suddenly go dark.
The National Highway Traffic Safety Administration says 128 owners have complained that low-beam lights can fail.
The investigation covers the 2005 and 2009 Buick Lacrosse; the 2006 and 2007 Chevrolet TrailBlazer, GMC Envoy and Buick Rainier; the 2006-2008 Isuzu Ascender and Saab 9-7X; and the 2007 Pontiac Grand Prix. At the time of the recall GM said the headlamp module in the engine compartment could overheat and stop working properly.
The agency says complaints came from owners of vehicles that weren't covered by the recall but are within the model years it affected.
The 2015 recall and a related one from 2014 covered about 497,000 vehicles.