New design to me:
http://www.atwoodmobile.com/refrigerators/
Before I try to use the gas mode I purge the gas line by lighting one of the burners on the stove.
Found this in the manual:
http://www.atwoodmobile.com/manuals/..._Manual_11.pdf
When switching to gas operation, the refrigerator control begins a 40 second trial ignition cycle. During this period, the control opens the gas safety valve and begins sparking the burner. If after 40 seconds the control fails to detect the presence of a flame, the control shuts off the gas safety valve and stops sparking the burner. The CHECK indicator on the control panel turns on indicating that the burner failed to ignite. The CHECK indicator can be reset by turning the refrigerator off and then back on again and a new 40 second trial ignition cycle begins. On initial startup or after changing a propane tank, it is possible that air in the gas supply lines will require 2 or 3 ignition trials before successfully lighting the burner.