If its clear water then sounds like ur drain is clogged up and ur hvac box is full of water. First thing I would check is ur drain outside on the firewall located about in the middle of ur firewall has tube opening with a bolt holding it in. Take the bolt out and remove the drian becarefull there will be like a gallon or more of water in there that will come rushing out. Then u can clean the drain while u have it out. Sorry I couldnt find a pic of what it looked like but its the only thing that looks like that in that area. Let me know what u find.