Re: 4Runner A/C Problems

Two conditions can cause this, The thermostatic cycling switch (or low pressure cycling switch) is responsible for defrosting the evaporator whenever evap temps fall below 32 degrees... if the system will not cycle..the evaporator will freeze up and restrict airflow and cooling. Also.. if moisture is contaminating the refrigerant, this can cause intermittant freezing of the TXV (thermostatic expansion valve) this would starve the evaporator of refrigerant.