how to vacuum out the coolant from ac ?

Hello, First, check that the A/C compressor is running when you turn on the A/C. If it is not running, the system will need to be evacuated, leaks/clogs identified and repaired, and then refilled. Refilling will not help if there is a leak or clog, and if the system has lost pressure at any point it will need to be evacuated. If the compressor is running, and you have one cold and one warm A/C line, the cause is likely the blend door which switches the temperature of air from hot to cold. It does this by directing air over the evaporator or the heater core, depending on what it is set on. The blend door could be broken or the blend door actuator could have failed.