I never found a spring-loaded lever either. There are two small plastic pieces on both sides but they seem to be just part of the shroud. In the end though, after removing the shroud and using spray air on it and reassembling…my printer now works. Only took me 2 months of trying other fixes, taking the whole thing apart, many hours of searching the net, and saying way too my expletives.
Great guide... The hardest part is that dang side window rail that goes all the way up. Now I just have to figure out why my motor will only operate clockwise. It's won't go the opposite direction to close the window.