i have a 92 mustang 2.3, have to jump start it every now and again, sometimes it shows alt not charging other times its up to where it should be. wheni have to jump it the battery is dead new battery, had alt tested and shows it is charging fine. took it off and took it to advance auto to have it tested. my tester doesnt show the alt working until i rev it up would it be the alt needs replacing cuz its not charging at low rpms? or is there something else like a bad switch that is draining the battery.
with lights on gauge goes low for nite driving.
any help appreciated thanks