You might take a peek @ the vacuum line (1/4"?) between the brake booster & fender, there's a "T" (directional) with a smaller line thru the firewall (to control dampers) & to under the ABS mod (1/4") thru the fender to evap canister.
(canister nipple sticks thru inner fender) luv those engineers
I found mine broken under there (with a small mirror) and removed (4) ABS mounting bolts and nudged it a little away to replace line
If it leaks/breaks, I think the airflow dampers won't move
luck,greg