We purchased our 2009 Bighorn 3385 RL six weeks ago and so far using it has not been a very pleasant experience. All the water leaks are now fixed, the plumbing vacuum breakers have been replaced, the converter has been replaced, and we only had kitchen faucet replacement left on our fix-it list. This morning we heard a new sound. The sound of some device venting has been intermittently coming from the vent under the Dometic refrigerator. The refrigerator seems to be operating normally. I can't find anything pertinent in the owners manuals. Please provide some clues as to what I should be looking for?