GE PGCS1R User Manual page 91

Humidity Sensor - Testing
Pins 1 to 2 --- constant 5 vdc.
Pins 1 to 3 --- varies with humidity from about 1.11 vdc to 3.62 vdc.
The higher the humidity the higher the output voltage. Any output
higher than @ 4 vdc or lower than 1 vdc, the sensor is bad
F.I. Testing – A reading of appx 0-100 would be considered normal.
A reading of 150 or higher indicates a failed humidity sensor.
NOTE: A failed sensor could keep the heaters on for longer periods.
Copyright General Electric 2011