I have a 2003 mits. galant es V6. My car feals like it's going to stall from the compressor or ac what ever you want to call it. Keeps shutting off and on one time it didn't turn on at all.

measure it,or get a fake pulley and remove the compressor

Sounds like the AC compressor bad

. Check for voltage on the Orange/Black wire in the C89 connector. The C89 connector is under the left side of the dash.
2002 Mitsubishi Galant, ES 2.4L, L4, VIN G, Des 4G64, 16V, USA *
Electronic Timer Alarm Control (ETAC) Module Wiring
- Missing a power to the ETAC.
you posibly need to replace

Electronic Timer Alarm Control (ETAC) Module Wiring

Water dripping onto the ground when the ac is running is normal.
Are you saying the engine dies when you turn the ac off ?

Ur evaporator drain tube is plugged it usually located under the hood passenger side fire wall use a piece of a coat hanger to get in there and un plugg it or compressed air will work to

a low freon charge will shut the system off to prevent compressor damage

Just one.

You will only see more then one on cars with true dual exhaust, which you usually only see on high end sports cars.

Try this web site for info on Mits Galants http://www.thegalantcenter.net/forum.php

this is the way the car is designed when the defrost is on it runs the are threw the evaporator with the AC on . this dries out the air to help defog or defrost your windshield. american cars have been doing this since the 80's . the original idea was to work the compressor in the winter. a AC system sitting not being used has more repairs than one that is used all the time.
i hope this helps

sounds like the fan controller switch in the panel has gone nutty. I would take the car to the dealer and let them diagnose the issue, they are best when it comes to knowing your car the most and in diagnosing problems with them better than just a regular joe blow shop that works on everything and doesn't specialize in any particular issue.