Got to be mechanical as it ain't electrical or hydraulic. 04 Chevy Avalanche. Has replacement blades put on at WalMart when I had the truck serviced a couple years ago. Road trip tomorrow and the passenger side does not wipe clean at all. Bought new blades at O'Reillys but it was raining hard and they were busy as heck so didn't ask them to put them on in the rain. Got home in the garage - read the instructions such as they are and cannot figure out how to get the old blades off. Couple different attaching thing-a-ma-jigs with the new blades that don't look anything like what is on there. Tried You Tube and as usual that was useless. Guess the new blades will go back to O'Reillys and they will either put them on or I get my $40 back. Use to be a simple task to change a blade in 5 seconds. My rant for the day.