Not sure if this helps or not. Our fridge in our volvo has a temperature control panel with one of the buttons for on off selection. I've never seen the set up in the international but if it doesn't have any direct on/off control that's a lousy design. Anyway if your truck has a on/off switch at your batteries just turn that off when your home on the weekends. Our volvos all have that switch directly behind the batteries inside the battery compartment.
Usually just rotate the temperature adjustment all the way down, should feel a click or indent when it rotates into the off position. My Western Star had a switch on the panel in the sleeper.