98 Explorer power window problem

I have been putsing around with my left rear window on my explorer and have not been able to figure out what the problem is.

I tested all parts. My motor works, switch works, regulator works. Window pulls up but never down. I had it all apart tried a different switch different motor and regulator and from a working side and the window will not come down. Any ideas??????

Thanks in advance for your time and efforts.

Same prob with front window of my 95 explorer. Discount auto wanted $100 for rebuilt motor. For $7, bought the rebuild kit and did it myself( it's only a couple of plastic parts).