Per Mike Ryan:
It always worked good until last night. There are no cars, this is a
rural area and it's pointed into my back yard on my shed.

How is it acting now that the snow has stopped?

I've been through several that keep coming on once temperatures drop
beyond a certain point..... i.e. they work during summer months, but
tend to stay on during winter.

Spent the big bucks on replacement sensors of a different brand (and
type?), but still having the problem.
--
Pete Cresswell