wait... what?? first off you lighting and you audio are on completly different cuircuits. second, LED's to a circuit is a short. this is y your blinkers are blinking fast. you need a load resistor to stop that. and third why the heck are you tail lights hooked into your speakers??????????? this would mean you lights flashes to the music. if you think it is the tail lightes than. unhook the tail lights and turn you radio on and see if it works then. but no offence with all you said, i would advise not doing any more electrical work to you car and to hire a pro.

 

yes. if you read a 0 when your wires are connected to the sepeaker and you use your multimeter to test it, you have a short. remove that speaker and replace it.

 

he meant the sound of the blinkers. in 07+ cobalts that comes from the speaker so he was worried the extra amount of noise the blinkers made from flashing to fast would hurt the speakers. this is not the case