Heater indicator lamp
Lighting: When the red lamp is turned on, electricity is supplied, and when the green lamp is turned on, electricity is supplied to the heating wire and it works as it heats up
Off: If the light does not turn on after plugging it into an outlet, the green indicator lamp is not lit because the outside temperature is not below freezing.
Power indicator lamp
When the plug is inserted into the outlet, the red lamp turns on to indicate that power is supplied to the sensor.
If it does not light up, you need to check it.