Car Air Vent Issue - Calling All Car Guys

Looking for help from the car guys here. My vents in my 2012 Mazda 3 are blowing something out of them that kind of looks like smoke but doesn’t smell and sinks instead of rises.
This happened before and I replaced the cabin air filter which seemed to have helped for a while. See video

We have had a ton of pollen in the air here that may be getting in. The “smoke” doesn’t smell or feel hot. No hot temp warnings from the engine compartment. No smoke under hood. Case has oil…
I am at a loss. Anyone have any ideas?

I am guessing you have condensation somewhere in the air ducting / tubing. This is when using the AC, right?

Yeah. It seems to not start until the system had been running for a little while (about 15 minutes or more).

Seems to be isolated to the vent system too.

I have been seeing water drops on the vents sometimes

If the vents are on full speed I can’t see it but on low speed or turning it off and on I get what is seen in the video.

Try checking if your condensate drain line is clogged. Here is a link to a guy showing you where it is on your car,


looks easy enough to do. Thanks.

Let us know if that resolves. I’ve put in a few vintage ac systems and they are really not that complicated. I can’t see it being smoke unless your blower motor is the problem. It’s likely vapor from pooled water.


I appreciate the help. It really doesn’t smell like smoke, either electrical or otherwise.

It’s raining out today but I will try and clean it out tomorrow. Makes sense if the drain is slow that the vapor only shows up after it fills when running for a bit.

Follow up - cleaned out that drain line about 1.5 weeks ago (there was some crud in there). Have not had the issue since, but it’s also been a bit cooler here so I don’t know if I have been running the a/c as hard.