No. Light has been flashing about an hour
Warm but not particularly hot.
How can I tell if the fan is running? (unless that is the humming noise)
Well, the good news is that the light stopped flashing. Nevertheless, I went ahead with checking the inside and found the back to be slightly frosty but not icy.
Then about a minute later, the red light started flashing again, and still is.
The machine was bought nearly 3 years ago and it has been full of food since then so I would not know what is involved in removal of the rear internal panel.