A year later, I decided to look into it. It occurred to me that there should be an exhaust somewhere on the exterior of the house where the dryer is blowing air out of. I went looking for it, and couldn't find it! This was crazy.

After a lot of searching, I finally found it - the previous owner(s) had blocked the vents - they were covered. I removed the block, and air could flow freely again.

And suddenly the sensor dry worked perfectly.

If yours is not working, do some debugging.