today morning my alternator went bad and overcharged my battery about 10mins. when battery started to overcharging my speaker stop working but the radio was on also battery overflowed. anyways~ i changed my alternator and my charging voltage dropped 16V to 14.3V so it's all good. when i start the car the battery makes spark noise. sometimes car won't starts (battery voltage drops till 3volts). also when i step on the brake all the lights(inside and outside) gets dimmed. when i let go the brakes it became normal. also sometimes radio turned off and turned on by it self.

here is the question..
do you think my battery cause the all this problem?

do you think there are short on the system?

please please share your ideas thank you..

 

Battery, but can't expalin the radio

 

Have the battery tested at a shop, and make sure your battery terminal connections are good and clean.

 

Take out the battery and battery box. Check that whole area for acid damaged wiring. If the battery overflowed, there could be a lot of it.

Mix up some baking soda and water to clean up any contacts/terminals that have corrosion.