Ac Drain

[cdx2]

Have water on the passenger floor board. Just started happening right after I replaced the alternator!! Fix 1 thing then another. I removed the ac drain hose and there does not seem to be any junk in there. But I did notice "with my finger" that there seens to be a foam "filter" right there that is soaking wet. Is there supposed to be a filter there? If not how do I get at it from the interior to see what is going on? I started looking at it and it looks like a pain so I am just trying to save some time Any thoughts? Thanks

[Rob_M]

Originally Posted by cdx2

Have water on the passenger floor board. Just started happening right after I replaced the alternator!! Fix 1 thing then another. I removed the ac drain hose and there does not seem to be any junk in there. But I did notice "with my finger" that there seens to be a foam "filter" right there that is soaking wet. Is there supposed to be a filter there? If not how do I get at it from the interior to see what is going on? I started looking at it and it looks like a pain so I am just trying to save some time Any thoughts? Thanks

I had a similar issue last year and took the car in to have it looked at while still under warranty. My wife noticed water dripping on her foot and that the carpet was wet while we were on a long drive. Otherwise, I wouldn't have noticed. It was hot and very humid outside. At first I though condensate was blowing back into the car after draining through the hose but the drain was properly positioned and working fine. The dealer checked the AC system and said there was no problem. I was determined to find out what was happening and I think I figured it out:

Just above the passenger side footwell is the evaporator unit (contains the refrigerant coils on the cold expansion side of the AC). The external surface of the unit will get quite cold when the AC is running. When the AC is not in recirculation mode the system draws in outside air. The AC unit removes some of the humidity from this air. However, when it is extremely humid outside, the conditioned air inside the cabin will have a higher relative humidity than it would on a less humid day (even though its still significantly less humid inside the car than on the outside). As the air inside the car contacts the cold evaporator unit it cools and water condenses on the surface. As the water accumulates it eventually drips onto the floor. Running the AC in recirculation mode would probably eliminate the issue since you would further reduce the humidity in the car prohibiting the saturation point from being reached.