2nd Gen Non-Engine/Transmission Wet Wool Smell

[Matt42]

When I turn on the heater on my 1996 (a rare thing to do here), the interior smells like wet wool for a while. After I run the heater for a few minutes, the smell dissipates but doesn't go away completely.



Oddly, while I had the truck in eastern Missouri in June, it produced a similar smell when it was rainy out, without the heater on.



Any thoughts would be appreciated.

Matt