My suggestion- recharge, put a green dye that you can see or red if you prefer that, let it run and you will see the leak. But you will have to recharge so that compressor kicks in. Use a dye that does not need UV light and special glasses to see it.
Some folks might suggest you to bypass the pressure switch and get the compressor to kick in with whatever you have left in there. But I am not so sure if I would want to do that.

MVK

__________________
One penny saved is three penny earned.

1985 300D Turbo 179,000miles