1. The power cord is not plugged in properly. Check whether the power cord is firmly connected to the socket and water dispenser.

2. Equipment failure. If the power cord is plugged in, it still doesn't light up. It may be that there is something wrong with the water dispenser and it needs to be checked by professional maintenance personnel.

3. Judge whether the lamp is damaged. When the water dispenser is started, the light does not light up, which does not mean that there is something wrong with other equipment. You can remove the light bulb to check if it is damaged. If it needs to be replaced, you can go to an electrical appliance store in JD.COM or an e-commerce platform such as Taobao to buy a suitable light bulb for replacement.

4. Power supply problem. If the above three conditions are excluded, it is recommended to check whether the power supply is normal. You can use an electric pen or multimeter to check whether the voltage is stable.

In short, if the water dispenser doesn't work, it's best to find a professional to repair it to avoid more problems caused by misoperation.