1998 Roadtrek 190 Dodge Chassis

I have not been able to open the window in the rear door of the Roadtrek for ventilation when the vehicle is not in motion and generator not running (assuming we get it to run). I loosened the interior screws (3 each) of the the two tilt out latches and found that the window is not stuck to the rubber gasketing along the bottoms and sides. I suspect the hinge that runs the full width of the window may be seized. I squirted WD-40 into both ends of the hinge and will give that a chance to work. Any other suggestions would be appreciated.

Also regarding the CO monitor, the light flashes green when I turn on the cabin battery. As I have no clue as to whether or not the monitor has ever been replaced I plan to install a new one. Just wondering why the flashing green.