Hello, I'm Danny.
Your fan blades are bolted to the fan clutch assembly.Here is a tutorial for you to see about removal and replacement.After removing you will have access to the bolts to tighten.Here is a tutorial showing what is involved:
https://www.2carpros.com/articles/fan-clutch-removal
I've attached picture instructions below for your Trailblazer.Hope this helps and thanks for using 2CarPros.
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Saturday, May 9th, 2020 AT 6:42 PM