AC hasn't been used in 15 years where to start?

MY opinion,BEFORE turning on with engine running.

1. Check for refrigerant pressure in the lines, if none, stop and check for leak
2. If pressurized,with engine not running but key on, turn on the a/c and see if the condenser fan runs. If not determine why. Same for evaporator fan.
3. Once fan runs, cycle compressor with thermostat, you should hear the compressor clutch engage.
4. If you get the above, make sure the manual heater valves are off, start the car and see if the system works, check pressures and balance charge. Double check the condenser fan is running.

Have fun with it. I would wire the condenser fan to be on any time the a/c is asked for and not to cycle with the compressor, the system could use all of the sub-cooling it can get especially if the condenser is still in the back of the car.

Angelo

I would be very surprised if there is any refrigerant left in the systema after that time.

The A/C system typicaly leaks down without use to maintain seals, most pantera's require an annual top up to compensate for winter losses whiel aprked.

If it has the original York piston compressor, then you are better off pulling the system apart and upgrading to a rotary compressor IMO.

Julian