I haven’t seen a 3 way fridge in ages. Typically they’ll run on gas or AC with 12V being used I both modes for the control circuit. But it shouldn’t particularly get warmer when driving. It should switch to gas automatically (if you’re set on auto, of course) but if the gas fails to light - which happens often enough - it’ll certainly get warmer until the next time it’s plugged in. There should be a tell light though that shows you if this has happened. Does this always happen?
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