check the bulbs themselves they sometimes short out internaly & cause feedback also check sidemarker lights I have changed all bulbs and fuses! Wiring problem???
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.
head lights
Break lights come on when you step on the break, they do not come on when the head lights are turned on.
If the headlights are on and brake lights work but not the tail lights, it is possible there is a short in the electrical wires. Another cause for this could be that the tail light bulbs are burned out. Most vehicles have more than one bulb inside the tail lights to control different lights at the same time.
The head light switch is shorting out ,or a bad connection
Since the break lights turn on when the head lights are activated, the problem is probably in the wiring of your break lights. Someone may have accidentally disconnected the wires of your break lights to your head lights.
It sounds like a blown fuse or a bad head light switch
its just a fuse, look for a fuse panel there are two. one under the dash and the other under the hood.
If you are parked and you want to here the radio without the Automatic headlights on. Some times if you engage the parking brake it will turn off the automatic head lights.
believe it or not you may haveblown fuse check them.
1 of 3 reasons why, your head lights are on, your reflector lights are on ,or your brake sensor is broken
How to adjust the head lights of 350e