How can I fix Renault Megane 2 electric window?

I have an 03 megane 2, the passenger rear electric window only goes down. I have tried the regulator on the other side connectors and it all appears to be ok. I have replaced the switch bank on the drivers door because when the wiring is swopped from front to back the fault moves with this, but the new switch does the same, although the window can be driven back up by connecting to the front switch. HELP PLEASE!