After replacing my failed sensor a few years ago, I spent two very frustrating hours trouble shooting...because it still wasn't working.
After double and triple checking everything, I finally came to the conclusion that as unlikely as it seemed...the new one must be defective.
When I took it back to ACE at Southern Trace, the sales person said...
"these are defective and I thought we got rid of all of them." 
I don't recall the brand, but if you buy a replacement from ACE...they should have all good ones now.