Charging System Problem

[jamesdrf]

Hi all,

I am having a problem with my charging system. A few months ago, my battery and starter died in my 2002 3.4 GT. I replaced the battery and starter - but the starter (from Auto Zone) died the next day and drained the battery. I got a second new battery, and a new starter from another store. The starter is fine and works, but after putting in both the starter and the battery, the next day I started up the car and my battery light came on. I checked the alternator and it came back fine. The battery was fully charged, all my connections on the starter are tight and secure. The battey posts were cleaned until they were shiny, and were tightened.
The battery light did not come on before I put in the first starter and battery. Could I have loosened a connection somewhere? What wires should I be looking at, and how can I fix it?

Thanks in advance,
James

[AaronGTR]

How did you check the alternator? If you just took it out and had them test it at the store, it could still be bad. I did that once... they told me it was fine but it had a bad voltage regulator. Their machine can't simulate voltage load from running accessories, and if your voltage regulator on the alternator is bad, the voltage will keep dropping until the battery light comes on.

If you have access to a mutli-tester or volt meter of any kind, try hooking it up to a power and ground wire somewhere on the car. Then with the engine running, start turning things on... A/C, head lights, radio, etc. See what the voltage does. If it doesn't stay above 13 volts and starts dropping into the low 12's and 11's, then replace the alternator.