IDK if it's been covered, I did a two page search, and nothing came up.
Converting non A/C cars to A/C is simple. Provided you get parts from the same MK# car as yours. All of the electrical plugs and holes are there already. All that is required is;
- a/c brackets
- a/c compressor
- a/c evaporator
- a/c condensor
- a/c belt
- all a/c hoses
- auxilliary fan
- funky idle control motor, with vacuum lines, the thingy with the white plastic screw on it, mouted just left of the ignition coil, on the firewall
- all additional electrical, including;
- WOT a/c disengage switch, mounted on gas pedal linkage
- a/c module, located on a/c evap. box
- all under hood a/c wiring
- all under dash a/c wiring
- a/c on off switch
Start by removing the black metal blockoff plate, next to your radiator. Install your compressor brackets, the compressor, and then the condensor related items, including the aux fan. Pop out your three black rubber plugs on the firewall, two for the pressure and suction lines, one for the evap coil drain. Remove the plastic duct between the blower and the heater box. Remove the blower box. Install the evap box, with the module, where the duct was. Reinstall the blower box. Install the a/c pressure/suction lines and drain tube. Install the WOT switch on the gas pedal. Don't worry, as you can adjust the on/off point later by bending the metal tab. As long as it clicks near WOT, it will work correctly. Pop out plastic plug where a/c on/off switch goes. Install switch. Install all wiring removed from the donor a/c car, both under hood, and under dash. Charge syatem. If all was done correctly, you have cold air.
On mine, the under hood electrical connectors were too corroded, and I had to butt splice them in. Also, make sure you have grounds for all of your new wiring, as it won't turn on if it's not grounded properly.