1, maybe the socket voltage is not enough. Haier electric water heaters generally have to reach a voltage of 220 V.2. There may be no power supply, tripping, leakage and incorrect connection of power cord. 3. It may be that the socket or the line is damaged. Suggested treatment: 1. First, check whether the socket voltage meets the requirements. Haier electric water heater needs to reach a voltage above 220v, otherwise it can't be turned on, causing the yellow light to light up. You can try it with an electric pen, or look at the instructions in the electric box, which usually shows the voltage. 2. Check the line for tripping, leakage and poor power connection. There are many branches in the electric box. Check whether the switch connected to Haier electric water heater trips. In this case, just type it again. If it is electric leakage, it is recommended to stop using it first and ask a professional master to come to the door to prevent accidents. If the power supply is not connected correctly, please reconnect it. 3. Check the use of sockets and lines. Frequent use of sockets will inevitably lead to failures. Just change it again. If the line is damaged, it will be more troublesome. Please ask the installation master of Haier electric hot water to reconnect the home line. It is suggested that the line is broken, or find the original factory, and don't mix other brands. After all, the original line is more secure.