Rear Window will roll up but not down. I'm stumped.

[Roadkill]

I haven't been able to roll down the passenger side rear window for a few weeks now. I took apart the door panel and replaced the window motor thinking that was the issue. When I went to test it, it would roll down every 20 or so tries and roll back up with no problem. The regulator did not appear to have any damage at all and the motor did not seem to strain when going up or down. The drivers door switch as well as the passenger rear door switch have the exact same issues so I'm not totally convinced it's a switch issue. I'm not sure where to go from here. What do you guys think? TIA.