my 2002 chevy blazer wont start. it started fine the last couiple days but today when i turn the key it just clicks once. the battery is full power on my display and lights and radio comes on. it is very cold today as well. not sure if it is starter or connections or what?

 

Your battery even though it shows full power the cca (cold cranking amps)
deteriorate with age. If its a new battery (unless from walmart) that might not be the issue.

On my blaze it would have trouble starting due to and improper ground from battery to engine block (to my alternator) It was actually connected to the frame. Once i put it right it started right up. though that might not be your problem.

If those check out to be ok than i would say its most likely your starter.