Update to whether or not block heater is operational.
1. Ohm check across hot and neutral of the plug for the heater: 19.8 to 20.0 ohms
2. 110 volts with 20 ohms = 5.5 amps (Ohm’s law)
3. Started generator, switched off inverter and charger. Amp draw on L2 = 2 amps
4. Plugged in the block heater. Amp draw = 8 amps
5. 8-2=6 within reason of the projected 5.5 from ohm’s law
Conclusion: all OK. Block heater element is good and circuitry feeding it is fine.
I was expecting a much larger draw on the generator at first, resulting in the original post. I was anticipating more like turning on an a/c and hearing the generator respond.
Thanks for responding and reading. Again, RV education. Every time I use it.
Anecdotally: LCD displays in the overhead are real slow and dim at 15 degrees above 0 F.