If your vehicle is equipped with the outside rearview mirror defrosters, they will operate at the same time you turn on the rear window defroster.
Kia Niro 2017 (DE HEV) Service Manual: Components and components location
Components Location
1. Hybrid Power Control Unit (HPCU)
2. Hybrid Control Unit (HCU)
3. Brake Switch
4. DC Fuse
HPCU includes the HCU (Hybrid Control Unit), Inverters ...
Kia Niro 2017 (DE HEV) Service Manual: Curtain Airbag (CAB) Module Description and operation
Description
Curtain airbags are installed inside the headliner (LH and RH) and protect the
driver and passenger from danger when side crash occurs. The SRSCM determines deployment
of curtain airbag by using side impact sensor (SIS) signal.
...