This indicator light illuminates:
• When the rear fog lights are on.
Kia Niro 2017 (DE HEV) Service Manual: Rear Door Trim Components and components location
Component Location
1. Rear door trim
...
Kia Niro 2017 (DE HEV) Service Manual: DCT Control Module (TCM) Components and components location
Conponent Location
1. DCT Control Module (TCM)
...