The switch recall covers almost 1.7 million vehicles - most of the automakers' model lineups from the 2007 through 2011 model years.
In addition, Hyundai is recalling about 194,000 Elantra compacts from 2011 to 2013 to fix an air bag problem.
A faulty switch can stop the brake lights from illuminating when drivers press on the pedal, the National Highway Traffic Safety Administration said in documents released Wednesday. Also, the cruise control may not turn off when a driver steps on the brake, push-to-start buttons may not work, 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. It was unclear if the problem has caused any crashes or injuries.
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. Both automakers are owned by the same company and use the same underpinnings for their cars and SUVs. But the appearance and driving characteristics are different.
Hyundai models affected by the brake light switch recall include the 2007 to 2009 Accent and Tucson, the 2007 to 2010 Elantra, the 2011 Sonata, the 2007 to 2011 Santa Fe, the 2008 to 2009 Veracruz and the 2010 to 2011 Genesis Coupe. Kia models include the 2007 to 2010 Rondo and Sportage, the 2011 Optima, the 2007 to 2011 Sorento, the 2010 to 2011 Soul and the 2007 Sedona.
The recall is in addition to a 2009 recall for a similar problem with the brake light switches.
Hyundai and Kia will notify owners and dealers will replace the switches free of charge. Kia will send notifications in May, while Hyundai expects to send them in June, after enough replacement parts are shipped to dealers.
In the Elantra air bag recall, a support bracket can come loose when the side air bags are inflated and cause injuries. In one case, the bracket cut a driver's ear. NHTSA began investigating the problem last year and traced it 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.
In April 2012, an Elantra owner told investigators a side air bag inflated in a crash and sliced the driver's left ear.
Hyundai dealers will install industrial adhesive strips to keep the brackets in place at no cost to the owners. Hyundai will notify owners during the second quarter of this year.