WARNING: This page is about a different car, the 2015 Kia Forte5, 2015 Kia Forte Koup, and 2015 Kia Forte. However, it is still accessible from the selected car via links, so may be relevant.
Check for continuity between the trunk lid open switch terminal.
Fig 1: Trunk Lid Open Switch Connector End View
Courtesy of KIA MOTORS AMERICA, INC.
If continuity is not specified, inspect the switch.
Fig 2: Trunk Lid Open Switch Continuity Reference Chart