Cadillac 2005 DeVille - Manual (Page 153)

To access the passenger compartment air filter, do the
following:
1. Use a tool to gently pry the cover up. If your vehicle
has tabs that allow you to unlatch the cover with
your fingers, you will not need a tool for this step.
2. Then, insert a tool behind the push pin located on
the inboard side of the air filter compartment to
carefully pry the pin out.
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