l have sound to all my speakers but l turn on my head lights and the system turns off and when l press the brake pedal the speakers cut out

WTF??? l have installed so many stereos and never heard of that?? Double check the wiring

You need to check the car is wiring program, because,
someone, does have their wires crossed. <}:-{(

you probably screwed up the wiring.

l think u better recheck your wiring, could be a bad earth or something

Well there is something else to check beside the wiring. A friend of mine had a truck that everytime he hit the brake the stereo would sut off, l replaced his alternator and the problem went away. So have your alternator checked out, it might be going bad on you. Any parts store will check it for you.