ddfarms, Mark is right on. If you aren't plugged into 110, the fridge panel will display both lights auto and gas. This means the fridge is set to go to elec as soon as you hook up to 110. If the auto light is not lit, it will stay on gas regardless, weather you're plugged in or not. If you're running on 12 volts only, be sure you have the ambient temp and climate control switches off. these are located in the freezer compartment in the door opening at the top. Find you're Dometic Fridge book. Hopefully you received it. It explains all you'll need to know. Hope this helps a bit.