Fridge troubleshooting

So, my motorhome is out on rental right now and the renter is having issues with the fridge. It's an auto igniting unit. Basically, he's saying that it works fine on setting #1. But if he turns it up to #2 or higher, the fridge shuts down and lights blink. I was always under the impression that the gas flow on these is the same no matter what temp setting you have it at. It's just a matter of run time (cycle time), that determines how cold the fridge stays. #1 having the shortest run time and #5 the longest. With that said, why is it turning off on him?

I've gone through all the basics with him:

-blow out the access panel
-moho sitting level
-voltage is good
-and yes, the propane valve is on