Ford is recalling about 850,000 cars and SUVs because of a problem that could stop the air bags from working in a crash. The recalled models include the 2013-14 Ford C-Max compact, Fusion midsize, Escape SUV and the Lincoln MKZ luxury car, all sold in North America. Ford says the restraints control module in the car could short-circuit, causing the air bag warning indicator to light up. If the short circuit occurs, restraint devices including the air bags, pretensioners, and side curtains might not work in a crash. However, dealerships will replace the restraints control module at no cost. Automakers have recalled more than 40 million cars and trucks in the U.S. so far this year, which is a record. Most of those vehicles have been recalled by General Motors, which announced early this year that a faulty ignition switch could cut power to the engine, knocking out the power steering or brakes and disabling the air bags if the car crashes.