Follow-up to this thread: Basement getting awfully damp while I wait for
the replacement sensor. In the end I took it to Sears for an estimate.
They acknowledged that it had 1 year remaining warranty on the sealed
components (but not the rest). Today (2 weeks after drop-off) I received
two messages from Sears on my answering machine.

The first message was an apology for the delay, and they would be
contacting me soon.

The second was a statement that Sears had decided to replace the
dehumidifier rather than attempt repair; and I would be notified shortly
when to pick up the new unit.

When I pick it up, I'll turn in the sensor for credit. All's well that
ends well ... though I suppose I won't know for sure now whether the
problem was the coolant or the electronics/sensor.