My range over microwave was installed with fan venting back into trailer. I read the instructions about reversing the blower to point outside, but there should be two bolts inside cupboard on top to swing microwave down. I can't find any bolts or anything to loosen it. Has anybody done this or know if they put cupboard bottom shelf in after the fact.
I had the same problem with our Country Ridge, and they just fixed it for me this week. Figured it out as when the vent is on, it blew back into the trailer, but was drawing air from outside through the vent.
The bottom of the cabinet is put in after the microwave is installed. Unplug the microwave, then very carefully you can pry the bottom of the cabinet up, sliding it to the top. The bolts are now visible on the bottom. There were a couple of screws, and the fan rotates. Note from my repair guy, test it before you reinstall to make sure it's blowing the right direction (out the back for our trailer and probably yours) and that the opening through the wall is completely open. Once it's back in, attach the bottom and plug in and enjoy.