the line off the supercharge tree that leads to the pass side fire wall, then it runs down the fender and under the fuse box, some cars have a T under the fuse box some dont, one side runs into a wire harness to inside the cab under the fan box, if you pull the carpet down you can see the wires, then the vac line runs to a bxx behind the dash. then to the vac pumps that work the air flow direction.
if you find a T under the fuse box the other side runs across the rad support and then under the driver side head light to a vac ball.
you want to follow this vac line from the sc top down and look for a crack in the line.
if you cant find any breaks in the line.
follow this thread http://www.grandprixforums.net/threa...door+actuators to get the dash open on both sides, then car running change air flow direction. watch the two round parts in the first diagram, its what changes air flow.
if they move but nothing happens, a linkage part broke, they fail on there own.
round part with a line to the top and the arm pushing out to linkage is what you want to watch, theres one on both sides of the dash
