I have encountered a problem that I wonder if anyone has found a solution. After my truck has sat over night, there is a strong mildew smell for about 5 to 15 seconds. This only occurs if I run the A/C up to when I shut off the truck. It is the worst if running max cool.

Here are the things I have tried:

1. Started running the A/C in normal mode most of the time and only used recirculation mode only to initially cool down the cab. Continued to smell mildew in the morning.
2. Sprayed Lysol into intake vent with fan on high. Sprayed approx. 5 second spray - helped but smell came back in a day or two. Really, the smell was still there with Lysol smell over the top of it. Frigi-Fresh worked a little better.
3. Turned off compressor and ran fan until air was no longer cool from the vents. An attempt to completely dry the evaporator before sitting all night. No smell the next morning.
4. Ran heater with compresser off to dry the evaporator before sitting in garage over night. No smell

The only way I can keep this from happening is running the fan on high with the compressor off for about 5 minutes or run the heater for a couple of minutes to dry out the evaporator. The drain pain is obviously not draining when the truck is immediately turned off with the A/C running.
Here is what I observed yesterday. I was driving around with the A/C running and pulled up into the driveway. Left the truck running and observed the water dripping from the A/C drain. It appeared pretty normal with water dripping about a drop or two every second. I had my wife turn off the truck. The water stopped dripping from the drain like the drain had been shutoff. Turned the fan switch to off and turned the key to ON (truck not running and compressor off). Switched the fan to 1, 2, 3 and HIGH. At fan setting 3, a lot of water blew out of the drain. On high, even more. Back to fan setting 1, the water stopped.
There is a lot of water remaining in the pan and explains why the mildew smell always returns. The water not draining is the root cause of the smell and if I do not fix this problem, the smell will return. I know I can run the fun with the compressor off to dry the evaporator out everyday, but I should not have to do this. I have never had an A/C system do this in 35 years of owning automobiles. There is something wrong that is causing this in this Dodge truck.


My question:

1. Why will the water not drain from the pan unless the fan is running on a high setting? Could it be due to the new design of the evaporator case?
2. Has anyone else encountered this problem?
3. How did you fix it so the water drains when the truck is shutoff? I don't want to have to dry out the evaporator everyday by turning off the A/C and running the fan.

 

Happens to me as well. It's normally just the first inital blast of air though. It doesn't last 15 or even 5 seconds.

I just deal with it. I don't run the a/c that much. Being as you're in Texas it's probably more of an issue for you.

 

My 05 Chevy did the same thing and I was unable to fix it. I live in South TX, where we run A/C 365.

 

Long shot. Was the truck on an incline when you observed this? Can you try parking so it's facing the oposite direction so the HVAC box can drain better?

G

 

No incline. My garage is pretty level.

 

Mine did that a while back and hasn't since. But my guess is a leak somewhere in the the duct, maybe through the upper outside vent below the windshield, or water is sitting and building inside the vents over a period of time for what ever reason. This shouldn't be happening and should be fixed at the dealer asap.

 

I took my truck in Thursday for this problem. The service department at the dealership is just great. The same technician has worked on my truck since day one. I had not noticed the water issue with fan speed at the time I took it in. I just knew if I ran the fan and/or heater to dry the coil out, there would be no smell.

The technician called STAR and they do not have a fix or cleaning procedure at this time. The evaporator drain exits the firewall horizontally facing forward. STAR directed him to install a 90 degree hose to extend drain down about 8". I think they were thinking maybe wind was keeping the water from draining from the case. The routing of the hose keeps the water from draining directly onto the frame which I like. Now the water drains directly to the ground. This is how I saw what was happening with the drain and how the fan helped the water to drain.

Given the amount of water that blows out of the hose when the fan is on high as explained in the original post, there is no way the hose will fix the problem. I do think the hose can help. I have to take the truck back to get the A/C head unit changed so it can take the latest flash. I will show the technician the water issue and see what he thinks and let you know.

I am hoping someone else has already had this problem fixed and I can just tell him what to do.

 

Hose did not help. When I cranked up the truck this morning, it smelled pretty bad. Looks like I will have to dry out the evaporator core everyday. I hope they can fix this!!

 

It's gonna take a few days for that smell to go away even if it was fixed. I'd get an odor eater air freshener and leave it in a few days, it will help even if the problem is still there, but hopefully it dries out for good. I used a Bright Air Odor Eliminator from walmart. It comes in a cup size plastic container that maybe your wife would be familiar with.

 

I live in Austin/Round Rock and had the same problem for the first 3 months of summer then it just went away by the way I use my AC non stop.

Oh and it only stunk for the first few seconds when I would turn on the AC.