Rep Power: 0

Hey all.
First time posting here looking for a little help. Car was driving fine no issues. Parked it for a day and then it wouldn't crank. When I release the key the needles go absolutely nuts and there is a ton of ticking. I've checked the fuses and they seem fine. Didn't see any blown ones relating to the alternator or ignition system. When I turn the headlights on the under hood fuse box ticks and I can feel the ticking in the ig1 fuse. Tried boosting but no luck. From what I've seen online it could be the battery alternator or starter. What's the best way to proceed here?

 
Rep Power: 208

disconnect battery,

test battery voltage,

12.5v or higher proceed,

12.5v or lower replace battery then proceed,

clean battery posts and terminals/connectors spotless with a mixture of water and baking soda,

dry terminals off,

reconnect battery and try again,

 
Rep Power: 0

It worked. Battery tested great. Corrosion on ground clamp. Starts. Thanks a ton.