Chrysler Repair: Air conditioning 2000 Chrysler Cirrus, metal grate, water jug

Question
I have a 2000 Chrysler Cirrus that the air conditioning recently quit working.  The fan does work, howver, the air conditioner blow warm air.  The interesting thing that I need info on is that under my front passenger seat, water has begun to surface, significant amounts of water- even when we do not have the vent, air or heat on.  The water jug is also going quickly.  There is a metal grate looking device under the seat. Can you tell me what this is?  I assume it is tied to the air conditioning.  Also, what do you foresee is the problem?

Answer
Hi Sandra,
I suspect that the water under the seat is actually coolant that has dripped out of the heater/ac box under the dash due to a leak in the heater core inside that box. Check to see if it is also wet on the floor between the firewall and the underseat as the water could puddle toward the seat if it is lower than the foot area. I have to admit that I don't know what the 'grate looking' device under the seat is unless it is an auxiliary heater core (which if so could be the source of the leak if it has separate hoses supplying it which you might see if you looked under the car at that same area, though I hadn't seen such a set up). In any case there is a leak in the circuit of the cooling system that supplies coolant from the engine to the cabin to operate the heater and that needs to be found and repaired so that you don't either loose enough coolant to cause the engine to overheat and be damaged or you have excess humidity and rust in the cabin.
Fortunately if the leak is at the heater core under the dash it is possible to replace that without removing the entire box which is often the case with other vehicles.
So take a look for those wet area things, and then let me know if you can find the primary source of the leak. Then we can move on from there. I would check the overflow bottle and the radiator cap area daily to make sure that you don't run out of coolant until you find the leak.
Roland