my 00 subaru outback dies if i turn on lights, or press brakes, or turn on anything electrical.

sell it

sounds like an electrial problem

Go to any mechanic or your dealer for service and check the wiring. The wiring must be faulty as your car is pretty old already. If it keeps 'dying' when you hit the brakes, safest is if you have it towed to the repair shop

obviously its something electrical...alternator..battery??? bad grounded wire.faulty wiring.who knows only a mechanic.

Check the battery earth lead

possibly:
1.) bad alternator
2.) bad battery
3.) short in a wire somewere

l have a 2000 impreza and it is still going strong. l would call the dealer or email subaru online and tell them what is going on. go to subaru.com and email them the year and the model and tell them what is happening.

If you have recently added a trailer hitch or any other outside wiring, check the connections for shorts. Also check the exterior light fixtures for leaks.

l think there is wrong in electrical power maybe from (bad)wires or from battery or from the alternator ..

More than likely a bad cell in ur battery. If u have an ohm meter, with the car off test ur battery- on the DC setting on the meter of course, u should have at least 12 volts. Next with the car running perform the same test & u should have a reading of 13 to 18 volts indicating ur alternator is good. This is the easiest & cheapest way to start locating ur problem. If u do not have an ohm meter find a friend that does or purchase one, they r not that exensive & can be a helpful tool to own