Corporate siblings Hyundai and Kia are recalling almost 1.9 million vehicles in the U.S. to fix two problems, one involving air bags and the other, faulty brake light switches.



The switch recall covers almost 1.7 million vehicles -- almost all of both makers' 2007 to 2011 models used the same switch. This recall is in addition to a 2009 recall for a similar brake light switch defect that can lead to several problems.



Separately, Hyundai is recalling about 194,000 of its 2011 to 2013 Elantra compacts to fix an air bag problem in which a bracket can come loose and injure occupants when the bag deploys.



The faulty light switch can lead to four potential safety problems, according to documents posted on the National Highway Safety Administration website: the brake lights may not go on; the cruise control may not turn off when the driver presses the brake pedal; push-to-start buttons may not work on vehicles equipped with them; and a feature that stops the driver from shifting out of park without a foot on the brake may fail.



"Failure to illuminate the stop lamps during braking or inability to disengage the cruise control could increase the risk of a crash," NHTSA said in the documents.



It was not known if the problem has caused any crashes or injuries. Messages were left Wednesday with Hyundai and Kia spokesmen.



Like many automakers, Hyundai and Kia try to use the same parts in as many cars as possible to get a better price from parts suppliers and make manufacturing simpler. But when something goes wrong, it can cause a massive recall. In this case, both auto brands are owned by the same company and use the same underpinnings for their vehicles.



For the switch recall, Hyundai and Kia will notify owners in the next two months, and dealers will replace the switches free of charge.



The air bag problem in the Elantra is that a support bracket can come loose when the side air bags are inflated and cause injuries. In April 2012, an Elantra owner told NHTSA investigators that a side air bag inflated in a crash and sliced the driver's left ear. NHTSA traced the problem to cars that had auto-dimming rear-view mirrors installed after arriving at U.S. ports. Technicians installing the mirrors could dislodge the bracket, the investigation found.



Hyundai will notify owners in the second quarter and dealers will install industrial adhesive strips to keep the brackets in place.