WARNING: This page is about a different car, the 2014 Hyundai Elantra GT and 2013 Hyundai Elantra GT. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Identifying Audio Remote Control Switch
Courtesy of HYUNDAI MOTOR AMERICA
Fig 2: Audio Remote Control Switch - Circuit Diagram
Courtesy of HYUNDAI MOTOR AMERICA
Fig 3: Identifying Audio Remote Control Switch Connector Pins