A healthy charging/electrical system won't do that. You may have something failing. Have your local auto parts store test the charging/electrical system, they may find a failing battery or alternator, assuming the engine is idling at the required rpms.
when there are oncoming cars, it is appropriate to dim your headlights when they are about 300ft away. Check your diver manual for the most correct answer.
Usually dim headlights are caused by a poor ground connection.
Yes. Far as I know all cars do. They dim for night driving and may not be readable in the day time.
the courteous time to dim your headlights is as soon as you see another vehicle, or within one half mile.
you most likely have a short somewhere in your wiring
Your headlights may not dim because you don't have dimmer lights. Dimmer lights can blow and leave you with just the high beams.
You should dim your headlights within 500 feet of the car in front of you. The rule of thumb is, if you can see another car, dim your lights.
If you can see the area lit by their headlights, then you are probably close enough to dim your own.
If by "dim headlights" you mean low-beams... the bulbs are bad and must be replaced.
The headlights on the 2002 Toyota Tacoma might work on dim but not on high beam because of a blown fuse. If the headlights are too dim to see properly in the dark, there could also be a problem with the alternator and the charging system in the vehicle.
100 feet
never