Through my own troubleshooting, I came to the conclusion that my diffuser was likely broken. After defrosting my refrigerator, the fridge section did get down to 34F but then went back to 50F. I figured the diffuser door was able to close, but not open again. I almost ordered a new diffuser, but then this post motivated me to try and fix the old one. My diffuser door was only broken in one place, so it was springy when I manually moved the door while assembled with a screw driver. I glued the broken door as recommended here. lubed the plastic guides and main sliding surface inside of the cam drive and it seems to be working great. I believe my worn lower fridge door hinge (which was cheap and easy to replace - there are two pieces and two screws - don't buy new screws) had cause a right door seal breach which over time caused a build up of moisture then ice in the diffuser. When the door is physically restrained by ice and the cam turns, the door breaks. I'll bet this is the most common problem w this unit.