I'm suddenly having issues with my 2004 G35 coupe. About 25% of the time when I go to the car it just clicks. If I jiggle the positive connection on the battery the car while then start. Now the alarm light is shining bright the entire time I drive. It blinks like it should when the car is off. Any ideas?

 

Sounds like a terrible battery connection, likely due to corrosion on the terminal. Get a brass toothbrush and a cup of water and baking soda and go to town on it. Once the corrosion is cleaned, see if that fixes the issues. These cars show very strange issues with a bad battery or battery connection.