... I was driving to work this morning and as I was downshifting to a stop, I noticed a really light fog-like mist come out of the vent! It wasn't smoke, didn't smell at all or anything. When I downshifted numerous other times, it didn't happen. It almost looked like condensation, or something, and I was running the AC. Anyone have any clue to this???

 

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I assume that the top was down (or Windows open), and it is hot in San Diego CA as well. It is alos humid there as well right?

I have this happen in all the cars I have ever owned here in Houston. The humidity and the cold air of the AC combind to create this "Fog". Here is Houston, it happens all the time, and you get used to it. I turn the AC down (temp up) the fan down. Also if you seal the car back up (top up, windows up) the humidity in the car will be removed, and the problem will cease.

 

Top was up

I'm certain it wasn't anything mechanical... but, who knows??? It's been a bit humid here.

Anyone else have any ideas?

 

Very normal. It was the cold air from the A/C condesing the moisture out of the air near the outlet of the vent. Usually A/C systems will do this right after the compressor cycles back on.

 

Thanks for the info! Reassuring to say the least!