Took a look at the link (manuals) Leeann provided. Quick scan ... your refrigerator is two-way (propane/120VAC) for main operation, with a 12VDC circuit for the management unit.
Clicking noise, if not coming from dash, could be 12VDC management unit trying to ignite the propane. (Didn't look farther but yours is probably electronic ignition instead of the older, problematic pilot light refrigerators.)
From my experience, propane and 120VAC are roughly equal in terms of keeping things cold/frozen, as well as chilling/freezing warmer items. (Both times with propane refrigerators, we had to dial back the temp control to keep them from turning jugs of milk into ice milk.)
The 12VDC mode of operation in older two-way (propane/12VDC) or three-way (propane/120VAC/12VDC) refrigerators didn't work very well, typically suited only for maintaining already cold temperatures. In these cases, the 12VDC was primarily for operating the refrigerator while driving. (On older propane refrigerators, you were supposed to shut off the propane before driving because the air turbulence would often blow out the pilot lights.)
Will try to add more later ... worn out from working on kingpins.
Two questions:
Is the clicking noise in the dash or in the refrigerator? Does it sound like metal on metal or like a spark? (The two sounds are distinctly different, even to me with my service-connected hearing loss.)
