Is my Alt. Bad?

[bluemustang00]

So I need some help to determine whether my Alt. has gone bad. Monday my car decided it was gonna be an isssue. I tried unlocking the car wit my alarms keyless and noticed my alarm light wasnt on so car had no juice.

Yesterday went got a new battery and battery terminals (ones I had were cracked) get that all repleced and car starts up just fine.

Me and buddy did notice a humming sound coming but couldnt tell where.

This morning leaving for work my car ran back to the same issue of no power. Buddy comes over we try jumping it and at first nothing then after a few of charging we tried again and it would make that cranking sound.

Buddy is gonna get his battery charger and we are gonna try it again and see what happens.

You guys think it could be a bad altenator? Cause I personally dont know

 

[89roadster]

Next time it's running, put a voltmeter across the battery terminals. You should be getting at least 12.5+ from the stock alternator, if not, there's your problem.

Are you sure you don't have a drain somewhere?

 

[bluemustang00]

We are gonna recharge it soon see what happens. But im pretty sure theres no loose connections or anything we checked pretty much anything that could possibly cause it.

 

[fost9508]

You can also take it to any reputable parts store and they should be willing to check the alternator for you. They have a little cart they roll out to your car the puts a load on the system. You will know for certain. The voltmeter test should work also. Either or.

fost9508

 

[BaXTeR3221]

Also if you get the car running with jumper cables and then the car dies when you pull them off, thats a sure sign your alternator is shot. Otherwise, it could be putting out some power, but not enough, which would lead to an eventual battery drain, but i would also check all the connections to make sure that the voltage is getting where its supposed to be.