It's an issue I have with salesmen at car dealerships in general. They have like 12 different cars probably max .... to me they should know everything they can about each.... they should be on forums like this learning details.... be a professional expert.
Looking online at other posts people say proprietary - so while similiar I myself would be worried the threading/little hole wouldn't match up perfect.
Why would the refrig not run long on a cigarette adapter. The adapter you posted is just a cigarette adapter (just with and adjustable cord).
I run mine for days via the cigarette adapter. The Dometic portable fridges were made to run that way - unless you don't have a portable one (looks...
Like this ... yea they are universal get from anywhere
https://www.amazon.com/SPARKING-Cigarette-Lighter-Terminals-Extension/dp/B07448P2GH/ref=sr_1_3?dchild=1&keywords=battery+to+cigarette&qid=1591016109&sr=8-3
actually - if you look closely at the video. After he enabled it and tried to get it to work … it didn't work and the seatbelt warning was showing on the dash (so he had his seatbelt off).
When he went to starting and stoping the car a few times and then tried again..... you can actually see...