"These vehicles could intermittently or permanently lose low-beam headlamps," said GM in a statement. "Until a permanent repair is available, dealers will replace the headlamp module with a new one of the existing part."
GM spokesman Alan Adler told Edmunds the automaker is "unable to confirm any crashes, injuries or fatalities related to this condition."
The expanded recall includes 159,584 vehicles in the U.S. and 20,920 in Canada.
In November 2014, GM recalled 316,000 vehicles for faulty headlights. They include the 2006-'09 Buick LaCrosse; 2006-'07 Buick Rainier, Chevrolet Trailblazer, GMC Envoy; 2006 Chevrolet Trailblazer EXT and GMC Envoy XL; 2006-'08 Isuzu Ascender and Saab 9-7X.
No information about the expanded recall has been posted on the Web site of the National Highway Traffic Safety Administration, which oversees vehicle safety in the U.S.
A date has not been set for the expanded recall.
Edmunds says: Owners of these cars should contact their dealer and make a service appointment for the interim repair.