Is the AC condensate drain clogged?

It is either engine coolant, rain / carwash water or a/c condensate water. Put a little of it on your finger and taste it. If it is sweet it is engine coolant and the heater core or heater hose is leaking. If it doesn't taste sweet it is either a plugged a/c condensate drain or a leak around the cowl or windshield. Please note: when tasting, antifreeze is poisonous in larger quantities.

I am pretty sure without tasting it is the ac condensate because it is ice- cold and will only show the symptom after long hours driving with ac on. The myth is the ac condensate is also draining to the ground. Dealer said it is the evaporator core clogged and needs to be replaced. Any suggestion to clean the clog without replacing the core?

So far I added a 90 degree elbow hose to the drain tube, which was just about less an inch coming out from the firewall and strong wind from cooling fans might have restrict the drainage. The drainage itself is seeming pretty good while vehicle is standing. Thanks.

Best of luck with it and please post a solution when you find it as it may help someone else.

Sure thing!

From the photo supplied it does not appear to be a leak so much as condensation is forming on the outside of the box every where. A leak would be more concentrated in one spot, this does not appear to be the case. Is there a outside humid warm air intrusion somewhere in the area? It does appear to be similar like if you place a glass of ice tea on a shady porch during the day the out of the glass will condense with water.

It does appear to be that way. But, the piece of foam on the box was soaked with water. So I suspect that water was back up inside the box with condensate.

But, I will check on if there is a leakage of outside air into cab. Thanks.

As Bob suggested being slightly low on refrigerant would cause ice to form on the evap. This could be the cause of the water when it melts. But is almost always results in a noticeable decrease in the temperature of the vent air. Easiest thing to do is to check the amount of refrigerant in the system to determine if it is low. You will need a set of gauges for this along with the spec guide on how to read the gauges as it relates to the ambient air temp when the test is performed.

I know it's been a while I have a 2010 expedition same problem what was the solution for your issue?