Toyota Repair: A/C leaking condensation into cabin, drain tube, rubber tube

Question
QUESTION: water dripping from A/C unit. Rubber tube appears to be clear but unit freezes up on bottom and then melts and drips into cabin on to passengers legs

ANSWER: What year and model is it and has anything been done as far as repairs go to the a/c system recently?

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QUESTION: 1993 Tray Back Hi -lux 2.4 litre Utility I think they were called Tacomas in the States

Answer
There may be a restriction inside the housing where the drain tube enter causing water to collect. Try blowing compressed air into the drain hose opening to see if it will clear up. If the passage is clear and the evaporator freezes up then there may be a problem with the expansion valve, I would then recommend having the system connected to an a/c analizer to see if the line pressures are abnormal and go from there.