I gently popped out the lower vents on my '85 to see why the vents won't stay open. Well, no wonder, there's nothing there to keep'em open! So, I took plain ol' rubber bands (black is better) and hooked them around the snap-tabs and across the vents. Works better than new! Don't overdo it with the bands though. You wouldn't want to stress the plastic parts. Check out the pictures.