The flow out of my dash vents isn't what it used to be several years back, reduced maybe by 30-40%. All of the selector modes seem to function properly but the flow from the vents just seems less. I see no leaves or debris near the cowl area at all and usually don't. Could there be some blockage at the inlet side of the evaporator core? If so is this area accessible for a quick cleaning? Any other ideas? Thanks for your help guys.