No gas to cook top

Solved! Back to high elevation (over 6000 feet) and all appliances, including Dometic cook top working fine! Unfortunately two changes were made, so I can't say with certainty what the fix was, but here goes. First, the cook top part with the at appliance regulator was replaced. Factor replacement part, same little regulator. In addition, the main RV regulator was replaced with a Marshall 253H, which a Marshall engineer said was fine. Did a manometer check on the Marshall with stove burners and water heater running. It showed 11.5 at home (2500 feet elevation). Made no changes to that setting. Now with all at just over 6000 feet everything is fine! Clearly, Dometic was lying when they repeatedly said that the cooktop would not operate above 4500 feet and were entirely unwilling to help. Bad company. IMO both changes I made contributed to the fix. If others encounter this issue, I would first change the main regulator to a Marshall 253H. That's the easiest and least expensive thing to try. Be sure it shows at least 11.5 WC. Or, before replacing the main regulator, make sure existing regulator is consistently delivering 11.5. I bought a Yellow Jacket manometer to do the checking. Check with gas flowing, say, to the stove burners.