I would not suspect a meter is the issue. I have never seen a bad one, but maybe there are bad ones.
Will your heater run at sunset? Will it run in the daytime?
Check that the wiring going to the heater is sufficient. Sometimes wires get broken (where there is just a few strands left), or corroded, and the wire can no longer carry the amps needed to power the propane fan motor (I think is what you have, not a electric one)
The fan motor on a propane heater should run even below 12 volts, though audibly slower.