Air Condition Unit

**UPDATE** - Finally had time to get up on the roof yesterday and pop the cover on the A/C units. The offending unit's coil fins were remarkable clean, but sure enough, the freeze sensor was dangling loose, not making contact with the fins at all. This one is a round sensor about the size of a quarter with a small clip that just pushes into the fins....I have pictures, but no way to post them. It simply would not stay put and I didn't want to ruin all the fins by trying different spots....SOooooo....wooden popsicle sticks to the rescue!! I was able to wedge the end of a couple of sticks between the plastic condensate tray and the sensor to get a snug fit that should stay put until I take it off, instead of it falling off during transit. I vacuumed the fins on both coils as well as all the leaves and stuff that had gotten inside through the gills. Then went back to the bedroom unit and did the same. That sensor was still inplace and operating fine...it was more like a temperature probe on the end of a wire that was shoved into the fins instead of a round sensor.

So my first assumption was correct, in that the unit froze up, but that was because of the freeze sensor not being in its proper place! If I can find a way to post pictures, I'll do that for everyone's future reference!

Thanks for all the replies!