Electrical, battery, relay issue??

Hello!! I’m new to forums so bare with me. Recently got my 1st quad. 2003 660. It’s been great until recent glitches. Went to start the other day. I pushed the button and get a single click from the relay then my display goes blank. Started looking for shorts and nothing. Decided to clean battery terminal then it works again!! Then today it does it again. I lightly tapped the positive terminal and it starts to work. So far it’s ok but I just don’t trust it. Any help would be appreciated!! Thank ya!!