Have Toyota Questions? Ask a Mechanic for Answers ASAP
When the problem is occurring, have you checked the system pressures with an AC gauge set?
The box in question is the ac control assembly
I would highly doubt that that box is the real problem. More then likely your expansion valve is damaged or plugged causing the low side pressure switch to turn the compressor on and off rapidly. Their is no way to check that with a gage set. as long as your evaporator is not restricted from air flow and you are not having the evaporator freeze and cause the temperature probe read too cold I would suspect a faulty expansion valve