In article ,
Shawn D'Alimonte wrote:
Mike S. wrote:
I haven't removed or opened it. It's a small white box with a grating in
front, sort of looks like those little piezo sound transducers. Has a
3-pin connector on the bottom. Will look more closely when I open the case
to install the replacement.

If it is the style I am familiar with it acts as a variable capacitor.
Something about a membrane that absorbs water with an electrode on each
side. When I used one it was in an oscillator circuit with a
microprocessor measuring the frequency. They are non-linear and
somewhat temperature dependent.

I was hoping you'd say there is a trimmer adjustment on the back :-) ....