I've never had that problem. Mine would cool just as well on AC as it would on propane.
Back when I had a Class B which had a fridge that also used DC power, when on DC power, it would at best maintain what ever temperature the fridge was when the DC power was used.
Perhaps your AC heater isn't up to snuff now?
92GreenYJ wrote:
I discovered with mine that it doesn't cool for **** on shore power. It will get mildly cool but that's about it. Doesn't matter what I set the thermostat to. These things are way more efficient on propane. I had it running on shore power for a whole week at max prior to a trip and it was barely 20 degrees below ambient temp. Got to the desert and fired it up on propane and the water bottles on the top shelf were frozen by morning. From now on I'm gonna just run it on pane a day before take off to chill it down.