According to NHTSA, the 2011-2013 model year Ford Fiesta vehicles have an air bag system designed to deploy the side air bags only when it detects the presence of a front passenger. However, that would leave right rear passengers unprotected from the subcompact car’s side curtain air bags should the Fiesta be involved in an side impact collision and could increase the risk of injury to these occupants.
As usual, you can get a free repair at your local dealership. Here’s Ford’s number: 866-436-7332. And here’s the campaign number: 12C26. Affected owners should be getting mail, too.