Looking online at the part diagrams, I can't seem to find a humidity sensor...

Here's my symptoms:

Dryer works fine on "timed" modes - dial it in for 40, 60 minutes, etc. and it works fine, runs hot, good air flow - no obstructions in dryer vent, etc.

When I operate in the "humidity sensing" modes - such as "optimum dry", "less dry" or "more dry" - the dryer runs, and eventually shuts off about an hour later - but the clothes are still damp.

I figure there is a humidity sensor that is not working - however I don't see a part labelled as such. I see a "cycling thermostat" on the discharge of the blower housing, and I see several other "thermostats" on the back of the drum itself. It's not clear to me which one of these is providing the feedback on % humidity to then turn off the dryer once a threshold is reached.

Any ideas? Thanks in advance! (Until then I'll use it in timed mode....)