Here to replace ECM blower motor for 2nd floor system. Remove screws from housing and disconnect electrical wiring @ motor to remove blower motor and assembly from cabinet. Removed old blower motor from assembly. Installed new blower motor. Adjust rotation to confirm no fringing noise from motor rubbing on housing. Installed blower motor in cabinet and secure electrical wiring. Ran and tested blower to confirm motor in back up and running. Switch thermostat from fan on to have system call for cooling. System is on running took temperature split @ equipment for supply and return. Supply temp 56.8F degrees return temp 78.8F degrees. To confirm AC system was back up to normal operation, check outdoor unit to make sure pressures were ok when I discovered that the system is short cycling @ 2nd floor condenser. Refrigerant line is frosting up and pressure is low @ 2nd floor system. There's a possibility of system having a leak or a restriction. Suction line pressure is 50psi over high side o