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: Pre-Charge Relay Specifications
Specification
Item
Specification
Contact
Rated Voltage (V)
450
Rated Current (A)
10
Coil
Operating Voltage (V)
12
Resistance (Ω) ...
Kia Niro 2017 (DE HEV) Service Manual: Components and components location
Component Location Index
[Engine Room]
1. Ambient Temperature Sensor
2. Receiver-drier
3. Condenser
4. Compressor
5. Discharge hose
6. The service port (voltage)
7. The service port (high pressure)
8. A/C Pressure Transducer (APT)
...