well a couple months ago my alternator started to hum. i didnt really think anything of it but it has gotten a little bit louder since then and tonight i was on the way home from my dads house about 20 mins ago. I pulled into my driveway and pushed on the brake pedal. the headlights went real dim and the sterio turned off. So i was like wtf. i gave it gas and the lights brighten up and the radio came back on. I shut if off and it wouldnt start up again so i jumped it and ran it for a few mins then shut if off then it started right back up. i have it on slow charge right now but is this a sign of bad alternator or bad battery or what?

 

You can pull the battery out and have it load tested at just about any parts store. If they say the battery is good i bet it is the alternator.

I want to say there is some sort of load test they can do to the alternator also, but I am not 100%sure

 

it sounds like an alternator problem, but to be sure, take it to your local autoparts store, they do free testing and they should be able to tell you if its the battery or alt for sure