I don't know what model Norcold you have, but we had a similar failure during recent thunderstorm with our older model 6282 Norcold fridge. I knew the 12-volt side was out when the auto feature did not switch to LP as it should have with just a 110-volt loss. The 12-volt fuse panel was all good, so I pulled the cover off the power control board on the back of the fridge as described above. A quick meter check found that a 3 amp "Buss" type glass fuse had popped on the 12-volt side. Once I replaced it from my spares kit, we were back in business. The temps only went up a few degrees while it was out, so there was no loss of any food.