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Discussion Starter · #1 ·
Greets all, I've got I think might be a weird A/C issue. Everything I've found on the internet talks about humidity and weird smells with the A/C getting turned on, but I've got humidity and weird smells when I turn it off.

When I shut the A/C off after it's been on for a while (while continuing to drive and leaving the fans blowing), the the dashboard vent fins get moist and moisture sometimes appears on the windshield above the defrost vent (with the other vents selected for airflow), this is within seconds of shutting off the A/C. The interior of the car will start to feel really humid, and sometimes it will smell also like a dirty sock once I've turned the A/C off.

Turning the A/C back on will of course solve the humidity issue, and the smell issue will usually go away as well. If I leave the A/C off, I can combat / temporarily cure the smell issue by blasting full fans on cold, cycling it to hot for a minute or so, and then back to cold. If I run the A/C again for 30-45 minutes, the smell will usually return. Most of my drives are too short to verify this recurrence of the smell for certain.

Now here's where I find myself in the twilight zone:

I've checked the A/C evap drain (the white elbow in the passenger footwell), and it was completely free of any obstructions. The rubber flex tube was also in great shape. I got under the car and checked the clearance between the heat shielding and the drain exit, and it seemed fine. I tested the drain elbow with a small watering can and it flowed freely and copiously onto the ground.

Thing is, the A/C doesn't seem to produce condensate while it's running (I live in the PNW and it's quite humid being springtime). I had the A/C running for 10-15 minutes in the driveway last week and nothing appeared on the ground beneath the car. I also tested it with the drain's flex tube removed, and the yellow upper drain elbow didn't produce any condensate at all. I ran some bicycle brake cable up through and beyond that upper yellow elbow to check for obstructions, and it came back clean. I changed the cabin air filter, which was definitely due for it, and used a mirror to inspect what I think is the condenser coil, and it looked clean and free-flowing save for two or three bent fins toward the bottom.

Even after all that, it still stinks and gets really humid really fast when I turn the A/C off. Any ideas?
 

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Had this happen to me last week after changing the cabin filter, take a strong vacuum to the vents behind your waterfall to clean the cabin temp sensor. i had a patch of condensation on the lower passenger half of the windshield that would go away during rain - hasnt returned after cleaning the sensor.
 

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Here in GA, it's always humid. I leave the AC on at all times just as a dehumidifier.

Make sure you leave recirculation turned OFF, as that will help clear out any humid air that's in the car. It's also worth checking that you don't have a heater core leak or sunroof drain leak if the car seems exceptionally humid.

All of my cars have behaved this way from old Volvos to new, Subaru, Ford, Porsche... I blame the climate.
 

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Ensure entire system is clean and dry, especially air intake. Clean out any organic matter

Clean ac condenser with anti mould spray. Garages have this. It kills the mould..

Afterwards, use VIDA and make sure you have afterblow activated to help dry the condenser to prevent further mould growth.


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Afterwards, use VIDA and make sure you have afterblow activated to help dry the condenser to prevent further mould growth.
That "feature" is P2-specific, it's not present on the P1. If you have found something to the contrary, definitely post it!
 

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Discussion Starter · #8 ·
OP here, just a quick note to say that things seem to be okay for now. It seems like a combination of a new cabin air filter, along with improving the clearance at the A/C evap drain tube exit, both contributed to better odor and humidity control - the warm, wet breeze I always got when I turned the A/C off has gone away, and so has the accompanying smell. Might have had a couple of things going on at once.
 

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Discussion Starter · #9 ·
OP here again, turns out I'm full of it. Original symptoms persist - when AC is switched off after running for a while, it's kinda funky smelling and kinda humid feeling, this is while running either fresh outside air or recirc (though I've been maining fresh outside air per suggestions here).

Additionally, I've noticed recently that for the first 10-15 minutes that the AC is switched on it blows cold air only intermittently - it seems to improve in performance over time after that, but I feel like it used to do better overall once it got to this "finally working normally" stage - does this sound like the AC clutch issue, a refrigerant leak, or some kind of control valve problem to anyone? I'm back in the twilight zone.
 

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Try a complete refill and replace your receiver/drier it is a consumable. But it does sound like moisture is stuck in your vents and going stale or organic growth has taken place in your vents. If you can stick a steam cleaner up your A/C drain and let it have it, also steam clean the the vents and try some Lysol in the vents. Spray some Lysol in the recirculation I take as well.
 
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