rear wiper arm won't lock down on 2005 Chevrolet Suburban 1500

I had the rear wiper blade changed and now the wiper arm won't lock down when it is shut off. If you turn it off it won't turn on again until you shut off the engine and manually lock it down.

Asked by for the 2005 Chevrolet Suburban 1500
It could be that the wiper arm is loose on the wiper motor shaft. Can you move the wiper arm to any position on the window when the wipers are turned off? If that is the case, the wiper arm will need to come off, the splines on the wipermotor shaft should be cleaned, and the wiper arm reinstalled in the correct position.
Being that the wiper parks sometimes and not others, I suspect there may be a problem with the wiper motor assembly which inculdes the control circuit board.
no it doesn't move freely when it is off. It catches on the block that it is supposed to rest on sometimes and other times it stops short of that, on the window.
I have seen this issue on my suburban. The replacement wiper blade may be too tall from the glass to top edge to fit into the parking block. Mine would strike the wiper arm instead when it tries to park. I bent my wiper blade assembly just slightly on the left side or center where it contacts the arm. This seems to have fixed the issue, but next time I will replace with the OEM part.