Tailgate Open Switch

Remove the tailgate trim.
(Refer to TAIL GATE TRIM Body - "Tailgate Trim")
Disconnect the connector from the actuator.

Fig 1: Tailgate Open Switch Connector
Courtesy of KIA MOTORS AMERICA, INC.
Check for continuity between the terminals in each switch position according to the table.

Fig 2: Tailgate Open Switch Terminals Continuity Chart

Courtesy of KIA MOTORS AMERICA, INC.