Remote Key Fob / Control not working

[Oscdav]

Hi, I have a question about my remote switcher, used to fire up my auxiliary heater. When I press ON the green light flashes rapidly for 15 seconds and then disappears, without firing up the Webasto engine bock heater.
Outside temp here in Norway -2C. Is the remote switch at fault or is the Webasto faulty?

Thanks, Rob.