I'm driving an s4 n/a, and having electrical problems. I have a recently purchased remanned alternator, from some generic autoparts store (napa, maybe?). I'm using an aftermarket CD player, along with a pair of subwoofers (not putting out much power). My car is progressively less and less able to keep the CD player running, which peaked yesterday when I was unable to get the CD player to even start. Usually, my voltage varies from 11.5 where the CD player cuts out and headlights dim, up to 13 where everything runs strong. My voltage readout was consistently 12.5-13.5 volts yesterday., but I still could not get the CD player to stay one for more than a minute at most. I experimented with every possible combination of headlights, air conditioning, and CD player. everything else will work fine all the time, but the CD player would not stay running.

So, here is my question. Is my reman alternator causing me problems? (I;ve heard of that happening before.) Is it just that the s4 alternator is not powerful enough to run a modern CD player, and I need to upgrade? Is my wiring bad, or is something improperly grounded?

fwiw, AutoZone told me my alternator was up to spec a couple months ago, but my problem wasn't nearly as significant back then. Also, my alternator has a lifetime warranty, so replacing that is the cheapest option, and will be my default if someone can't tell me decisively that I have another problem

 

Use a multimeter check for volts at cd player for the constant power supply and the switch power supply, make sure they are in spec. Then check resistance from the plug at the back of the cd player with a known good ground. Check to see if the problem happens only when moving (most likely loose wire) or when bass is turned up (possible loose wire).

Was everything working well with the old alternator before it pooped out? I have put 4 different remans into a car, all deciding they didn't want to work before I got it refurbished my an auto electric store near me.

 

#1 Is it a remanufactured alternator or a rebuilt one. There is a big difference. Remanufactured means all worn parts are replaced, while rebuilt means all broken parts are replaced. It is very very common to see problems with rebuilt alternators and not unusual to need to replace a rebuilt alt several times before a good working replacement is found.

#2 You have a voltage problem. Without the radio on, you should never be under 13.5 volts. If you are there is not even sufficent voltage to charge the battery. If you are dropping under 12.6 volts, then you don't even have enough power to run the car and are running in the battery. Most radio's die at around 7-9 volts, but some of the cheaper non regulated units can drop off at anything under 11 volts.

#3 your bump hase been deleted. Bumps are forbidden here in the 2nd gen technical section.