Mitsubishi Repair: 02 Galant with no heat, water shut off valve, refrigerant

Question
The dealer tells me that it will cost $900 to replace the Heater Water Shut Off Valve in my car.  I can't believe it's that difficult because all that's wrong is that the heater control knob doesn't allow heat inside the car.  Where do I find out more info on this so I can do it myself?
Have you had this type of problem before?

Answer
Raul: You need to go buy yourself a repair manual for your car. Then you will see there is a lot more to that heater water shut off valve. And what it takes to fix it, really $900.00 is not a bad cost in this day and time with the high cost of labor. They are going to have to take the whole heater unit apart. And doing so they have to remove the refrigerant, you have to have a EPA-approved container to put that into. But then before any of that you have to be so careful because the whole unit is under high pressure. If you do not know what you are doing, you could get hurt or even killed. So this is why it is so costly to fix that heater water shut off valve. But buy the repair manual they cost around $20.00 at any parts store and see if you really want to do this. Hope this helps and good luck! Linda