I haven't done it on an 09 Ram but it's similar to most newer vehicles. Suck down refrigerant and drain the coolant. I would disconnect the battery, unplugging all the dash may make something geek out. Dash must come out and then the HVAC box, split it open replace evaporator and back in. Figure at least a day. I prefer to take the front seats and console if equipped out. Makes it much easier to maneuver the dash and many times you can lay the dash right there instead of hustling it out a door. Good luck with it. Total pain in the a$$.