pass side, take the foot cover off, then take all the molding off at the door so the carpet can be pulled back. pull tthe carpet back so you can see the fire wall. just under the fan a box there you'll see a load of wires enter the car, one is the black hard vac line from under the fuse box.
follow this line it the console, theres a box back therethe line runs to, then 2 yellow lines leave it to the vac pumps in the dash that change the air flow.
does all that work? the def, floor, vent. like you can change it still? if not id think that box is suspect for sure. or the line running to it.
car running listen for a hiss under there, or a cracked line. work the controls while listening. you'll hear air when its changing air flow, but it stops.
