This is an old post, but I had the same issue. If you can't clear the clog by snaking a wire or something from the drain in sun roof, you have to take off the interior trim next to the windshield. If I remember correctly there is a hose coupler connector there and my Escape had bits of debris stuck too big to make it through the coupler. It should take about 10 minutes to disassemble. If it's the rear drains, it's a little more involved, but it is similar process with the interior side trim panels.