Try pulling the retained accessory power relay. It's on the top of the fuse box, and the breaker is on the bottom of the fuse box,
Where is fuse box located on 2003 Chevrolet Impala?
Under hood fuse box diagram for 2003 Chevrolet Impala?
http://technoanswers.blogspot.in/2012/02/under-hood-fuse-box-diagram-for-2003.html
See the fuse box Diagram shown below :----
This will help.
Thanks.
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