[NiftySVX]

Run the self diagnostic by holding OFF and AUTO buttons while turning the ignition to on. If memory serves, the air mix door and other servos' positions are detected and any stuck servo will display an error code. An easy way to check the refrigerant charge is to run the a/c and watch the compressor, it should never cycle off. If it does, and there are no error codes, it is probably low on refrigerant. Don't have the system retrofitted if it needs recharging, call around until you can find a local shop that has R-12 on hand if you have a 1992 year model.