tj90

Good question. I'm not sure. I installed this alternator about a month ago - all the connections were good back there. I read that the alternator self excites above 2k rpm but mine did nothing when I revved it up. I can't fully explain what I witnessed in failure condition. We're all 3 lines at 13v because the line was essentially open and there was no return path thru the excite line back to battery? But wait the excite line isn't grounded....

marc abrams

Well if you sure that the alternator is self exciting a loose belt would most likely be the cause. Otherwise we may never know.