Have HVAC Questions? Ask an HVAC Expert for Answers
Hello, there are over 10,000 different AC configurations on the market, if you can give the brand and model number that will help a lot... if not a few photo's will help, use the attach files link to the left of your send button for that.
So far it sounds like the cooling coil has developed a block of ice around it that is stopping the air flow, and the ice melt water in its drain pan is making the 'shower' noise.
So far it sounds like you are talking about the 'return air vent' and that the cooling coil is indeed iced... 4 or 5 pics taken from about 8 feet away will give me a better idea of what you have. Meantime turn the power off to the unit to let the ice melt, that will take 4 or 5 hours.
We can go from there