Belt TENSIONER System
WARNING: This page is about a different car, the 2006 Chrysler PT Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
Courtesy of DAIMLERCHRYSLER CORP.
The seat belt system incorporates Tensioner Modules. They are integral to the seat belt retractors (1) and cannot be serviced. If found defective they must be replaced.