I am trying to make my windsheild defroster work again..I have heat, but can't get any air up to the defrost vents. I have crawled under the dash, and the little vacuum motors do nothing went the control buttons are pressed, I unhooked the line to the white plastic tank behind the center consol and felt no vacuum, heard no hissing. This my be a too basic question, but where under the hood is the vacuum that powers the hvac valves supplied from? If I can find that, I think it would help me find the source of the problem.
thanks in advance,
straining to see in frosty Maryland