Why doesn't my air compressor cycle on and off instead of staying on always?

What is your question?

Truck blows cold air but compressor does not cycle and eventually Cold air slows down from vents almost like system is freezeing up because of compressor not cycling on and off . cause the blower motor continues to run but just will not produce any air until you turn AC off at dash and let blower flush all the frozen slush and then it starts to blow air again and then you can turn on air conditioner switch to get cold air what could it be ?