Weird Odor coming from fridge

[Jonesy]

The fridge, when I started it up this morning upon departure, emitted this awful smell. I guess I thought it was food I left in the fridge last night, and didn't think much of it, until I realized that not only was it still giving off this smell, it also wasn't cooling, but the freezer was, and did not have this smell.

After much reading in my manual and on the net, all I can find is stuff on ammonia, but this is NOT an ammonia smell. I am thinking maybe it's a ventilating issue, since all the vents on top are likely either frozen or covered with snow. Thoughts?

We have the furnace running since we are in cold temps, but we have turned the fridge setting to electric since we are in the campground.

Thanks,

Jonesy