I have the same problem as the OP. My heater never gets hot, and only consumes about 0.5 - 1 kWh. The outside temp has been about 40°F.
Also, once I turned on the A/C and the kWh dropped to 0 and it blew cold, moist air (fogged up the windshield). I turned A/C off and it jumped back up to about 0.5 kWh. I toggled it a few times and it was consistently dropping to 0 with A/C enabled.
I have the climate control timer set for the morning, while plugged in, and it is never warm when I get in. I'm hoping this is just a matter of replacing a fuse. Any ideas?
(Used 2013 Leaf SL)