Is my moisture sensor (YL-69) broken?
I think the device that you purchase is a “dew sensor” (ON-OFF), and not a humidity measurement device.
Then you have to specify what humidity you want to measure: the absolute, the relative or the specific humidity? See here

The most common used is the relative humidity (%RH). In this case, temperature should be considered. A typical sensor for this measurement you can see bellow



For specific application please see Si7005 from Silicon Labs