Simple fix. In the middle of the firewall under the windshield, under the hood, is a small check valve in the hard plastic vacuum hose. It's the size of a stack of two nickels. Replace it with one that's about two inches long and 1 1/2" in diameter. It has a small storage chamber to prevent the loss of vacuum during acceleraion or when going up long hills.
The system is spring-loaded to default to the defrost position for safety reasons. If the system isn't working properly, your feet might freeze but you'll be able to see.
The dealer's parts department has the new check valve, but you can also find them in the salvage yards.
Sunday, March 21st, 2010 AT 7:38 PM