Spray 4- to 6-quart slow cooker with cooking spray. Place pork ribs, onion and garlic in slow cooker.
Cover; cook on Low heat setting 8 to 10 hours.
About 35 minutes before serving, drain and discard juices from slow cooker; wipe edge of cooker clean. In measuring cup, mix barbecue sauce and jam. Pour or spoon mixture over ribs, coating evenly.
Increase heat setting to High. Cover; cook 25 to 30 minutes longer or until ribs are glazed. Serve ribs with sauce.