Most likely is that one or both of the bulbs have failed. Many cars use separate bulbs for low beam and high beam, so one set failing will not stop the other.
Once you have replaced the bulbs, if they are still not working check:
Fuses
Wiring, especially the earth connection at the bulb holder
Switch
change the light bulb that does not go on, on low beam, it possible that the wire inside the bulb for low beam is broken
Yes
there are two diff types of bulbs. High beam and low beam bulbs. If your low beam doesn't work then you need to replace those lights because they are probably blown.
High beam light is out!
No the high beam filament is independent from the low beam filament You can run them seperately or together . it depends on how the lights are set up. For instance if you have your high beam on you may have your lows running at the same time, however if your low beam is on low beam setting, your highs are always turned of It sounds like you may need to look at your fuses or your switch.
the high and low beam work on the same bulb... if your low beam isn't working the problem is electrical
Bulbs blew
If one headlight works on high beam but not on low beam, it typically indicates a problem with the low beam socket, the bulb, or the wiring specific to the low beam circuit. The high beam setting often bypasses certain components, allowing both headlights to function even if one low beam is faulty. It could also be due to a blown fuse or a bad connection in the low beam circuit. Checking the bulb and connections for the non-working low beam is a good first step in troubleshooting.
Because there are two light bulbs and the low beam bulb is burned out
Usually yes.
Bulbs, fuse, wires ,switch.
"It's possible that you blew the low beam filaments. I blew my high beam filaments while charging the battery." --MM