I have a 1990 4runner, when I run the A/C or the vent for outside air to pass thru I get this awful dusty smell. Any suggestions of what I should investigate to clean this up, it's terrible. Smells like a dusty attic or something

Hopefully it will be gone. It never worked in my Camry and I sprayed a ton of it. That smell is nasty. Diluted bleach seemed to help but it just won't go away and my '99 runner has a little ofthat too. Seems to be a Toyota A/C thing. The smell is from mold growing on all the wet dust and organic debri stuck in the A/C air ducting and heat exchanger fins. To really get rid of it requires opening it up and cleaning it out at big expense. Try turning off your A/C while keeping the fan going for a few blocks before each shutdown to help dry out the system before you park. That won't help either but it sure sounds like good advice.

You may ahve a point there. I have to admit, I use recirculate all the time.

Where I live, it is 115 degrees everyday, I drive this 4runner maybe once a month shouldn't it be dry in there? Or d'ya think the mold is so old, I gotta bust it open n clean it out???