Why Can't the High Beam Be Turned On in Mercedes' Automatic Mode?

[DeclanDella]

The reason why the high beam cannot be turned on in Mercedes' automatic mode is due to the high beam obstacle setting in the vehicle. Taking the 2021 Mercedes A180 as an example, it belongs to the compact car category with body dimensions of 4419mm in length, 1796mm in width, 1432mm in height, and a wheelbase of 2729mm. The 2021 Mercedes A180 features a MacPherson strut front suspension and a torsion beam rear suspension. It is equipped with a 1.3L turbocharged engine delivering a maximum horsepower of 136PS, a maximum power of 100kW, and a maximum torque of 200Nm, paired with a 7-speed dual-clutch transmission.

[OJuniper]

I've been driving a Mercedes-Benz E-Class for three years and have encountered a sudden malfunction of the automatic high beam. That time, I was on a rural night road where it was completely dark, but the high beams wouldn't turn on. Later, I found out that the camera above the windshield was covered with insect residue. The automatic high beam system in Mercedes is quite delicate—it stops working with just a little dirt. Moreover, it has activation conditions: the speed must exceed 30 km/h, there must be no streetlights, and no vehicles within 500 meters ahead. I even checked the manual specifically, and it mentioned that if a non-original windshield is replaced, insufficient light transmittance can also interfere with the camera. My suggestion is to first clean the sensor area, then check in the car's system to confirm if the 'Intelligent Light Assist' function is turned on. If it still doesn't work, it's likely a control module issue, and you'll need to take it to the dealership for a computer diagnostic.

[LeHope]

I've encountered several Mercedes-Benz owners at the repair shop complaining about automatic high beam failure. First, check the camera area at the top of the windshield interior – fingerprints or window film can affect light sensing. Mercedes' intelligent lighting system is highly sensitive; even reflective road signs can be misinterpreted as oncoming vehicles. Vehicle speed is also crucial, as the system automatically locks low beams during low-speed urban driving. Focus on three key points: whether the high beam assist setting is enabled in the vehicle system, whether the windshield meets light transmittance standards, and whether there are any fault codes in the body radar. Last time, an S-Class malfunctioned due to short-circuiting sensors after rain. If you can't handle it yourself, I recommend using an OBD scanner to check fault records.

[StHolden]

Last time when I drove my friend's newly purchased GLC, I encountered the issue where the automatic high beam wouldn't activate. Mercedes' DISTRONIC system has quite stringent requirements: it must be in complete darkness, vehicle speed above 60 km/h, no oncoming traffic, no street lights, and the camera's field of view must be clear. I also noticed that installing dark tint film on the windshield can cause misjudgment, as the system often thinks it's not completely dark yet. There's also a specific way to operate it: you need to turn the light knob to the AUTO position and then push the control lever forward. If the 'High Beam Assist' is turned off in the settings, it definitely won't work. I recommend first cleaning the windshield camera area thoroughly during a car wash, then testing it on the highway. If it still doesn't work, you'll need to check if the control unit is water-damaged or defective.

[EmmettMarie]

My cousin's GLE had an issue with the automatic high beams last winter. It turned out that snow accumulation on the windshield was blocking the sensor camera. Mercedes calls this system MULTIBEAM LED, and its activation conditions are quite strict: it must be completely dark, the speed must be at least 40 km/h, and there should be no taillights from vehicles ahead or headlights from oncoming traffic. If the lighting button on the left side of the steering wheel is accidentally pressed, it will also force the high beams to turn off. There's also a hidden issue: when the battery voltage drops below 12 volts, the system automatically shuts off the high beam function. It's recommended to check the lighting settings in the manual and reset the system by holding down the return button on the left side of the steering wheel. If that doesn't work, you'll need to check if fuse number 29 in the fuse box is blown.