DETROIT (AP) - General Motors is adding more than 588,000 vehicles to a recall to fix ignition switches that can shut off engines and cause crashes.The company says it's adding Saturn Ion compacts from 2003 through 2007, and Chevrolet HHR SUVs and Pontiac Solstice and Saturn Sky sports cars from 2006 and 2007.The additional vehicles increase the total recall to 1.37 million. GM announced Feb. 13 that it would recall 780,000 Chevrolet Cobalts and Pontiac G5s from the 2005 through 2007 model years.GM says the problem has been linked to 31 crashes and 13 front-seat deaths.GM says a heavy key ring or jarring from rough roads can move the ignition out of the run position, cutting of the engine. If that happens, the front air bags may not work.Copyright 2014 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.