The windshield wipers have started hanging up mid-wipe on my '04 V6. Turning them off and back on helps but they only go back and forth 2 or 3 times then hang up again. They don't always stop in the same place but it's generally mid-sweep. I've heard the problem could be the motor, the multi-function switch or the GEM (which Ford no longer makes). Any idea on how to isolate the problem and where I could find a GEM module if that's it? Thanks!