This has puzzled me since we changed our van last September. We've not gone anywhere far enough yet for the fridge to be on long enough to know if it is working off the car.
In the old van, the fridge had a red light to show if the fridge was working off the car.
In our new one, there are no indication lights to know it's on. It only has a gas indicator, and nothing for electric or car. You just turn the dial to whatever you want to run it off and it auto ignites if on gas.
So, can anybody suggest how I know if the fridge is working off the car, without leaving it running or a few hours? I'm not sure of the model number of the fridge but attach a photo if it helps.