chevrolet/trailblazer/2002-2008

2005 Chevy Trailblazer - 6 cylinder.

Changed the spark plugs yesterday and it started up just fine. I have been running with no tail lights. License plate light works, brake lite works, turn signals work, flashers work but no tail or running lights on the back. All lights on ther front work.
Today I went out and it would not start not even a turn over or click. I put the battery charger on anyway and it has a full charge. The negative terminal on the battery seems to be striped and will not tighten securely. I cleaned both terminals, and used some aluminum as a shim on the negative side. (Post are side mounted)
All dash lights come on when trying to start but nothing. I have checked all fuses under the hood and all appear to be good. Any ideas? Thank you!

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