The AC outlets (3 prongs outlets like the ones at home), including the one the air conditioner and/or refrigerator/powered cooler is plugged into in the electrical compartment only have power when you’re connected to shore power with your extension cord.  It’s also always good to make sure you are plugging into a good outlet at your campground and have tested your extension cord.  People have called reporting that their outlets are not working when plugged in and it was simply a non-functional outlet or bad extension cord.  A simple AC outlet tester or any AC appliance can be used to test the outlet at a campsite if you know you’ll need AC power.