First, check the defogging function key and ensure that it is functioning properly: make sure that the front and rear windshield defogging keys are working properly. If the keys are damaged or malfunctioning, they may need to be replaced.Check key identification: The front windshield defogging key is usually marked with a sector and three curves, while the rear windshield defogging key is marked with a rectangle and the same curve.
再检查空调系统，检查空调系统是否正常工作：按下除雾键后，空调系统应自动调整为冷风模式或热风模式，并将风向吹向前挡风玻璃。如果空调系统故障，可能需要检查空调压缩机、风扇、加热器等部件。检查空调滤清器：如果空调滤清器堵塞，会影响空气流通，导致除雾效果不佳。建议定期更换空调滤清器。
Recheck the air conditioning system and check if it is working properly: After pressing the defogging button, the air conditioning system should automatically adjust to cold air mode or hot air mode and blow the wind direction towards the front windshield. If the air conditioning system malfunctions, it may be necessary to check components such as the air conditioning compressor, fan, heater, etc. Check the air conditioning filter: If the air conditioning filter is clogged, it will affect air circulation and result in poor defogging effect. It is recommended to regularly replace the air conditioning filter.
然后检查加热丝和电加热功能，检查加热丝是否正常工作：部分奔驰车型配备了后风挡加热丝和外后视镜电加热功能。打开“后风挡加热”开关，不到一分钟后车窗应变透亮。如果加热丝损坏，需要更换加热丝。检查电加热功能：如果车辆配备了电加热功能，但无法正常工作，可能需要检查相关电路和控制模块。
Then check the heating wire and electric heating function, and verify if the heating wire is working properly: Some Mercedes Benz models are equipped with rear windshield heating wire and external rearview mirror electric heating function. Turn on the "rear windshield heating" switch, and the car window will become transparent in less than a minute. If the heating wire is damaged, it needs to be replaced. Check the electric heating function: If the vehicle is equipped with electric heating function but cannot work properly, it may be necessary to check the relevant circuits and control modules.
以上方法都不行的话，又特别着急的情况可以采取使用除雾剂，使用防雾剂：在车窗上均匀喷涂防雾剂，然后用干布擦拭至透明，效果可持续1-2周。也可以使用自制的除雾剂，如将洗洁精和水按1:10的比例混合，喷在玻璃上并用干净的抹布擦拭。或者手动擦拭：在确保安全的前提下，用干毛巾快速擦拭玻璃。并且调整车窗角度：适当调整车窗角度，使驾驶员更容易观察到车后的状况。
If none of the above methods work and you are in a particularly urgent situation, you can use a defogger. Use an anti fog agent: evenly spray the anti fog agent on the car window, and then wipe it with a dry cloth until it is transparent. The effect can last for 1-2 weeks. You can also use homemade defoggers, such as mixing dishwashing detergent and water in a 1:10 ratio, spraying it on glass, and wiping it with a clean cloth. Alternatively, manual wiping: While ensuring safety, quickly wipe the glass with a dry towel. And adjust the window angle: adjust the window angle appropriately to make it easier for the driver to observe the situation behind the car.
