I'm not sure what you mean by that. Usually low beams have its own coil, high beams have its own. They work on separate cirtcuits.
Bulbs, fuse, wires ,switch.
Bulbs blew
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.
Possible that both dip beam bulbs have blown
First check the bulbs, if the bulbs are good I would suspect the high/low beam switch is bad.
the bulbs in your car have two filaments, high beam and low beam. as you generally use mainly low beam the filament wears out a lot quicker than high beam. so replace your bulbs, as it couldn't be anything else.
My two guesses: 1Your high beam bulbs may be burnt out 2the high beam/low beam switch may be broken.
May be a bad switch
Because there are two light bulbs and the low beam bulb is burned out
Replace your dimmer switch and this should fix your problem Or both bulbs could be bad
The high low beam switch is bad or the hot wire to the high beam is damaged or broken
Fuse or bulbs burned out. On most they are separate bulbs or high beam filament is broken if 2 in 1 bulbs.