Bulbs burned out, possible headlight switch
This may sound like a stupid thing, but turn up the dash light dimmer, they will be bright while the headlih[ghts are off because its supposed to be daytime, but once the lights are switched on nighttime rules take over and the dimmer controls the lights intensity.
A weak alternator and/or battery.
The most obvious suggestion to this is that pressing and releasing the brake pedal while the ignition is switched on
Brake lights should NOT be effected by the headlights. Brake light function is completely independent of the headlights. Assuming you are not refering to the tail lights, or marker lights, which are supposed to come when the head lights are turned on. Not having brake lights when the head lights are on is a big safety problem and should be corrected.
bad fuse or relay switch
On my 2004 Modus the lights automatically go out as you open the drivers door.
Perhaps the high beam part of the lights are rs
that means that the bright bulbs are going or their out
This is usually an indication that the dimmer switch is in need of replacement.
go slower. leave your lights on. turn on your fog lights(if you have them) and do not turn on your bright lights!(in heavy fog) it will make it difficult to see for you and other drivers.
It means your bright headlights are on. You can control bright or normal with the turn signal lever. On some vehicles you just pull it gently towards you until it clicks to select bright or normal. On some newer models you push it gently away from you until your bright lights go to normal mode. Normal driving is with the blue light off.
The Kia Sorrento instrument panel lights go on and off with the headlights. The headlights go on with an automatic daylight sensor.