Plenty of other vehicles have rear windows that open while driving, and I find it hard to believe that the airflow on those vehicles is THAT much different.
I would be more worried about that flipper glass just flopping around open. Seems like it would be prone to breaking?
If none of the "easy" solutions work, what I would do is find out which sensor checks to see that it's open and throw in a bypass switch. I assume a connection is either made or broken when that flipper is closed, and I imagine you can fake it with a little toggle switch fairly easily. But try clicking the rear light first, maybe that will just turn off the light?
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Jeff 2005 Jeep Liberty Renegade
4x4, 6spd, Leather, Sunroof, trak-loc, skids/rails, hitch+shackle, hooks, Alpine/iPod, Thule, GPS, CB, Frankenlifted w/ 31" MTRs
Photos Cardomain