"recirc" setting not working

1998 grand Voyager, 3.0 Liter. Until a couple of days ago pushing the "recirculation" button in activated a damper, or something... behid the dash and also seemed to speed up the fan, so I'd get colder air at maybe a faster velocity.

The last 72 hours or so I'll push in the button and it'll light up, but there's no change in air flow and temp wether it's toggled on or off.

(I'm getting reasonably decent cooling but the extra oomph is called for some days...)

Anyone know how much work it'll likely take to get to wherever the problem is?

Thanks for any suggestions.