does anyone know what wire is the sending wire??
What kind of car you got, what year, and more information needed to give a quality answer.
Thanks.
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Misnblu.com
Newbie member since 1999
Thank you Dave and JBO! 
clicking on his user name would have told you it's an 05 cavalier.
On the post cat sensor I believe it's the brown wire on the pre cat I'm not sure.
