From Andy at InlandRV:
2 small 1/8 inch holes can be drilled into the window frame.
Start at the bottom and angle the drill upwards about 75 degrees.
Start the hole about half way up the metal frame of the window.
You want the drill to come out between the 2 panes of glass.
Drill slowly AND CAREFULLY.
The take a solid wire, like a coat hanger, and push it thru the holes, so that you make the holes in the sealer a little larger.
Then the water will drain.
Do not seal the window afterwards, as the problem will start all over again.
Tried drilling it as per your instructions and it worked great. Caulked the top of the window as it had dried up and pieces were missing. Thanks for the advise.