Tailgate Switch

Check for continuity between the Trunk lid open switch terminals.
With Back View Camera

Fig 1: Checking Continuity Between Trunk Lid Open Switch Terminals (With Back View Camera)
Courtesy of HYUNDAI MOTOR AMERICA

Fig 2: Checking Continuity Between Trunk Lid Open Switch Terminals (Without Back View Camera)
Courtesy of HYUNDAI MOTOR AMERICA
If continuity is not specified, inspect the switch

Fig 3: Trunk Lid Open Switch Connector Terminals Continuity Chart
Courtesy of HYUNDAI MOTOR AMERICA