They're not slipping or anything, they just don't stop at the bottom of the windsheild. When on delay, the wipers go all the way up and then all the way down, they just come back up about 6 or 7 inches before they stop. Then they continue there normal cycle for the delay. The problem is, when they return to the bottom of the windshield, they don't stay there, they come back up the 6 or 7 inches then stop.