friend wants me to check out his blower motor or sometihng. says when it rains and fogs insde, the passengers side will be clear because of warm air blowing to the vents to defrost the windshield, but the drivers side doesnt blow squat. pretty dangerous.. should it be the blower motor or the vents are clogged? if so where can i buy the stuff to clean it? i dont want to pop open the whole dashboard and crap. thanks a bucnh