[dave92cherokee]

The conversion parts you need to convert it from the old r12 to r134a can be bought at a parts store along with everything needed to fill the system. However unless you are a licensed mechanic to work with the refrigrant then the EPA can come down on you hard for not disposing of it correctly. When dealing with a refrigrant change like you are it's best to take it to a shop and let them deal with the hassle of changing and refilling the system. As for the a/c control unit to remove it (if it's like my 92 sport) remove the plastic bezel piece that goes around it and the radio and the guages and there will be a couple of screws that hold it in. Remove the screws and pull it out and disconnect the two electrical connectors from the back and using a flathead screwdriver you can disconnect the vaccum lines on the back as well then disconnect the steel cable that goes down to the door assembly. Alot of times it's the switch that selects it that goes out mine only works on low and nothing else.