Ok.thanks for replys guys, and I have one more question related to the battery. As I said before, battery in my car was weak from the day I bought a car. After few months my CD charger broke down. I took it to the repair and they said to me that some wires on the board melted down because some component (transistor or something I`m not sure) on the board was broken and use too much currency so as a result of that, wire has been melted. I took unimeter and find muself broken wire on the charger`s board.
Is it posible that weak battery could produce this?
Tommorow I will take my car to the mechanic, but I`m just currious could week battery can cause mailfunctions on electric components?