How do you know when an alternator is going out. Had a problem the other day that when i went out to start the truck it would not start. Battery was completly dead. battery is good. had to jump start it and took it a while to charge. I hear a ticking sound at times. It just started doing it.

 

With the truck idling, disconnect one of the battery terminals. If the engine stays running, then the alternator is good. If it dies, then it is bad.