< are you saying that the fans won't come on if the refregerant isn't at full charge even if the a/c is OFF? That's what it sounds like you are saying, and you may be right, but how does that make any sense? If the coolant temp is too high there should be a separate system that turns on the fans.
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Correct ...There are TWO fan circuits
They just share the same fan/s motor..
The low speed fan is the a/c aux fan and is activated by the preresistor relay/ a/c pressure sw. So , if you are shy of freon, don't expect to see this fan come on...[ that is why we always jump the pressure sw first thing when concerned about a/c aux fan .. very common to have no fan w/freon shortage--this quick test tells the tech the integrity of the fan circuit]
The other is high fan--- activated by high aux fan relay/ECT sensor ... this aux fan is for cooling the engine and has Nothing to do with low a/c fan circuit...different relay, sensor, fuse , etc,]

ECT and CT are different names for Engine coolant temp/collant temp sensor ...