Ask a Mechanic Online and Get Answers to Your Car Questions
We have a possiblity two things happening, the first is the alternator is not charging the battery or there is a drain on the battery.
Have you checked to see if the alternator is charging?
Do you have a volt meter
The first thing we need to do is find out if the alternator is charging the battery if not the following test need to be done.
Check the voltage at all 3 of the wires at the alternator with it running.The S and L terminals should have over 10 volts and the output post should have the same voltage as the battery.The L terminal of the alternator is grounded by the alternator until it starts charging and then should go to B+. Unplug the connector and check for near battery voltage on the wire with key on. Verify that the charge indicator light comes on when the wire is grounded. This circuit "excites" the alternator to start it charging.
If the alternator is charging we will need to look for a drain on the battery.
Hope this information is helpful, please accept my answer and leave a positive rating before leaving the site.
Do you need further information?
How was it tested? What was the battery voltage during testing?
It needs to be tested on the vehicle to make sure there is not a wiring problem to the alternator.
The battery needs to be fully charged and then preform the test, I sent you.
Try charging the battery and do the test I sent you.