I always have to jump start my S5 NA. So something is draining the power big time. I turn the car off and then try restarting but its always out of power. When I press on the brakes. My lights dim down then rebrighten so my BAC is working correctly Im guessing. But most of the times I press the brakes my aftermarket cd player shuts down then turns back on. It was ghetto wired from the previous owner. Can it drain it out that bad if it was wired wrong? I was guessing that it couldve been my alternator too, but all my idiot lights arent on when the car runs. Any ideas? The battery is pretty new still.

 

I'd start by ripping out the stereo and wiring it up correctly.
Your lights shouldn't dim when you apply the brakes.
Someone has screwed up some wiring somewhere and it will eventually Damage something.
Get it fixed while you can.

 

Disconnect the negative battery terminal and with the multimeter set to amps (red lead of meter also needs to be set to read amps ---- set to DC10A plug in). Then place negative meter lead to negative battery post and positive meter lead to the negative cable/clamp and see what the amperage drain is. Then go to the interior fuse box and pull a fuse and then check the amperage drain once again and see if there is a change and continue to pull a fuse and check until you see that the amperage drain dwindles to practically nothing. No key necessary and don't leave the door light on (door open w/light on) as it will create an amperage drain.

 

Also, disconnect the wires (3 of them. 2 in the plug and the third being the B+ terminal)) to the alternator and see if this is the cause for the drain.

 

have u had your battery checked? is it holding a charge? are your terminals clean and secured ie not coroded, have u had your alternator checked( ive had ones that produced just enuf power to keep car running, but would not charge the battery)

 

Thanks much you guys. Will do whats been recommended asap