Dometic refrigerator RM3762 RM3962 won't run on AUTO Mode and AC operation

[fotoman1527]

I am posting a problem I recently faced - and the solution! - in the hope that it will help someone with the same issue.

Many thanks to nvestysly for all the brainpower behind solving this problem!

I have one of the above Dometics in my 2012 Flying Cloud. For no apparent reason, the refrigerator control panel above the freezer lost the ability to display the option to run on alternating current (shore power), notwithstanding the fact that the coach was on shore power. It would run on LP. If you look in your installation and operating instructions you can see the lighting sequence for the panel, and the stop for "auto mode and AC operation," showing that the unit was running on AC, was not showing. The bulbs all lit up when the refrigerator was turned on, so I knew a blown bulb on the control panel display was not the problem.

I confirmed shore power to the coach by running a system that would not work in its absence - air conditioning. Dometic customer support asked me to further confirm power to the outlet in the outside refrigerator compartment, which can be found on the outside of the coach in the area of the back of the refrigerator. After opening the hinged compartment door (bending a wire hanger and using the awning's cloth loop to anchor a wire to hold the door up!), I unplugged the refrigerator and plugged in a fan, which worked. I thus reconfirmed I had AC to the refrigerator.

The solution came from removing a fuse in that compartment, which was blown. There are two, and the glass fuse, shown at the end of the arrow in the photo, was the culprit. The fuse I needed was a GDC-5A, T/250 IED 127-2.

A separate issue, as yet unsolved, is why the fuse blew in the first place.

Since this problem was eminently solvable without having to hire an expert, I pass the case along in the hope it helps someone else!