The Dometic refrigerator SP-219 in our 2019 Lance travel trailer 2465 works perfectly on electric but on gas it will start, then when it reaches temperature, it cycles off and the #3 and #7 lights start flashing, and it will not cycle back on. I can turn it off, let it warm, turn it back on, and it does the same thing (and will not cycle back on). I'm level, thermostat position is correct, flu is clean, batteries are in excellent condition, and all connections have been checked. The problem persists whether on shore power or battery power. The problem began intermittently a few months ago but in the past few weeks it has become the norm. Any suggestions?