Microwave shuts off in 14 minutes

I haven't found a similar topic thread with a similar microwave oven issue.  We bought a new 2014 R-Pod 179 last year.  During the walk-around inspection, we found that the overheat shut off switch was missing from the backside of the microwave (when the top vent of the slide out was removed).  The dealer installed a replacement switch and sent us on our way.  On our first camping trip we were cooking frozen dinners in the microwave and it lost power after 14 minutes of use.  The breaker was not tripped and every other circuit in the camper still had power.  After 20 minutes, the microwave power came back on.  We were able to cook for another 14 minutes and the power tripped off again.  This seemed to be the thermal safety switch kicking in.  I took it into the dealership.  They had it in their service bay for three months and could not duplicate my complaint, indicating that they could run it for much longer on microwave and convection without any shut off.  We towed the camper up to our ranch in northern AZ (270 miles from home) and parked it on the new property.  While cooking frozen dinners, I noticed that the door glass was fogging up and the thermal switch kicked in again at 14 minutes.  It is too far to tow the camper back over the mountain grades to take it back to the dealer for just a microwave problem.  Does anyone know if there is a vent port on the microwave that might be plugged (from the factory) that was not removed when the dealer set it up?

My thoughts exactly.  If they had operated it with any type of liquid in it, it should have tripped.  It acts like the oven is not properly vented, and with a convection function in it, there should be some type of vent port.  Since it immediately fogs up, that vent is probably still sealed.

Originally posted by Kdstaller My thoughts exactly.  If they had operated it with any type of liquid in it, it should have tripped.  It acts like the oven is not properly vented, and with a convection function in it, there should be some type of vent port.  Since it immediately fogs up, that vent is probably still sealed. I plan on taking the full tool set up to the ranch on our next visit.  One microwave-ectomy coming up.  Does it simply pull out from the front with all of the facia fasteners removed?