Why are the low beams on but the high beams not working?

[LaAngelina]

The issue where the low beams are on but the high beams are not working is due to a damaged high beam bulb. Here are some relevant details: Separate high and low beam headlights: Among the vehicle's lighting systems, there are integrated high/low beam headlights as well as separate high and low beam headlights. In this case, it involves separate high and low beam headlights, where the high beam bulb controls the high beams and the low beam bulb controls the low beams, using a separate control method. Car headlights: Car headlights, also known as car front lights or car LED daytime running lights, serve as the 'eyes' of the car. They not only affect the owner's external image but are also closely related to safe driving at night or in bad weather conditions. The use and maintenance of car lights should not be overlooked.

[OZachary]

Last time my car had the same issue—low beams worked fine, but the moment I switched to high beams, they just died. The main suspect is the dedicated high beam circuit! First, check the fuse box under the steering wheel for a fuse labeled ‘High Beam’ or ‘HIGH BEAM,’ pull it out, and see if the thin wire inside is broken. If the fuse isn’t blown, it’s likely the high beam filament is gone—don’t underestimate this; it’s in the same bulb as the low beam filament but operates independently. Another possibility is aging contacts in the headlight switch for the high beam—my neighbor’s old car had this issue, and the switch made a weak ‘click’ when pressed. If you can’t fix it yourself, just head to the repair shop. Driving without high beams on mountain roads is too dangerous, especially when you can’t see distant road signs around curves. Oh, and cars with modified bulbs are more prone to this problem.

[LeAmy]

I've been repairing cars for nearly a decade, and high beam failures are mostly concentrated in three areas: First is the high beam filament burnout, especially the halogen bulb filaments which are particularly fragile; Second, check the high beam relay - look for a black square the size of a fingernail in the engine compartment fuse box, give it a shake and if you hear loose parts rattling inside, that's likely the culprit; Third, inspect the combination switch (that control stalk on the left side of the steering wheel) - when the copper contacts inside wear through, it causes poor connection. Here's a pro tip: Some vehicles with automatic headlights will flash warning lights if the computer can't detect high beam signals at night, even when you're using low beams. If you're handy, you can remove the bulb to test resistance, but for most people, just try replacing the bulbs first - it's only a matter of a few dozen bucks.

[Clarence]

I've encountered this issue too, don't panic yet. Open the hood and locate the headlight connector, unplug it and turn on the high beams. Then use a test light to probe the corresponding high beam pin on the connector. If there's no power, it's a wiring issue in the vehicle; if there's power, the bulb is burnt out. For wiring problems, first suspect the high beam switch pedal underfoot - truck drivers all know this component tends to develop poor contact after extensive use. With newer vehicles it's more complicated - the high beam signal passes through the Body Control Module (BCM), and if the BCM crashes it can also cause high beam failure. Restarting the infotainment system might help. Remember to regularly inspect headlights - vehicles with yellowed reflectors should be polished immediately. When brightness is insufficient, we instinctively switch to high beams more frequently to check road conditions, which actually accelerates bulb burnout.

[KendraAnn]

As a female car owner's firsthand solution: First, reach under the steering wheel to locate the fuse box, find the high beam fuse (usually a 15A blue small square) by referring to the manual, and try replacing it with a spare fuse. Second, ask someone to observe your headlights while repeatedly switching between high and low beams to see if there's a slight flicker—this indicates the circuit is working but the bulb is about to fail. Third, go to an auto parts store to buy the correct bulb model; letters like H1, H7, or HB3 are printed on the base of the old bulb—don’t get it wrong. Finally, a reminder for those who switched to LED: off-brand drivers are particularly prone to causing high beam malfunctions—I learned the hard way and had to replace three sets before it stabilized. Repair costs are usually under 200, so don’t get scammed.