03 Fiesta Passenger Window Not Going Down

Hi all please help. I've just spent nearly 2 hours trying to figure this out , not including trips to scrapyard and dealers! As the title says the passenger window isn't working. I have a brand new passenger switch and a spare regulator from scrapyard. I know it goes up as by plugging in the spare reg it turns when up is pressed but not down. Also if I plug the passenger switch into driver side and driver to passenger it goes up and down on the passenger side but not the driver side switch . It's confusing the he'll out of me so any help would be greatly appreciated. Thankyou.