Stock Westy wiring only permits the 3 way fridge to run on 12 volts
while the engine is running!

The fridge does not require 12 volts for anything other than running
while set to 12 volt operation!
(the cooling fan on the back does need 12 volts to work but the fridge
will heat the ammonia without it and cool the interior)

To check 110v AC operation the most reliable way is with the power cord
from the fridge plugged into a 110v source directly, not using the 110v
power distribution of the Westy.

Mark