1, one of the three switch lights is not on, the internal contact is poor (fastening the wiring), the switch light is damaged (replacing the switch light), and the corresponding electric heating tube is damaged (beyond repair).

2. The switch lamp is completely turned off or not heated, resulting in poor internal contact (fastening wiring), damage to the main thermostat (flashing thermostat) (replacement of debugging thermostat), damage to the socket (replacement of special socket) and damage to the power cord (replacement of special power cord).