A National Highway Traffic Safety Administration manager recommended almost seven years ago investigating why air bags in some of General Motors Co.’s Chevrolet Cobalt and Saturn Ion cars weren’t deploying, a memo issued by the U.S. House Energy and Commerce Committee shows, Bloomberg News reported yesterday. The chief of NHTSA’s Defects Assessment Division e-mailed other officials in the Office of Defects Investigation in September 2007, saying owner complaints from 2005 and “early warning” data about warranty repairs and injuries justified a probe, according to the memo today from the committee. Congress is investigating an ignition-switch defect that can lead to air bag failure and has been tied to 13 deaths. NHTSA chose not to open a formal defect investigation in 2007 after reviewing the air bag data, according to an interview between current NHTSA officials and the House committee’s staff. That decision and the recall of 2.6 million cars this year are set to be the main focus of hearings this week, in which GM Chief Executive Officer Mary Barra and acting NHTSA Administrator David Friedman will have to explain their handling of complaints of stalling cars and air bags that didn’t deploy.