What is system voltage while engine is running? Also ensure part is properly installed (electric connections too).
my battery is still on after changing battery and altnator
Your alternator is dead!
If the light is still on then the problem was not the battery but was instead the alternator which is more than likely defective.
Battery light usually means alternator not charging. Most common solutions would be be a bad alternator, bad connection, or loose alternator belt. If the battery and alt test ok than check the connections to the alternator and battery. The alternator should have 2 connections.
The battery has a temperature sensor. If it was left unplugged, the battery light will still be on
Battery light usually means alternator not charging. Most common solutions would be be a bad alternator, bad connection, or loose alternator belt. A replacement alternator can be bad. If it is ok than most likely a poor connection to the alternator.
It could be an alternator. Check with a mechanic if that is the issue.
Your belt is correctly tensioned?
Battery light usually means alternator not charging. Most common solutions would be be a bad alternator, bad connection, or loose alt belt.
Sometimes an alternator with a weak diode(s)can test out fine, but can still trigger the light. I believe the problem is in your alternator. Good luck.
you have a short where negative is touching the metal of the car or it is grounded inproperly
If the light remains on then the system still isn't charging as it should. Check the plug on the alternator and also that the wires to the alt have a good connection.