Hi all:
The defroster vents on my 1994 LWB always blow air no matter what (and it increases the faster I drive). Is this a vacuum leak of some sort? I've checked the vacuum reservoir under the hood but it looks like the hose has no crack. Where else can I look? Is it possible it's the right vertical slider switch on the heater control that needs replacing (the footwell/defroster control)? Thanks.