have a look at the wiring harness that runs from the b pillar to the leading edge of the door ..
there will be a rubber plug with a connector that all the wiring runs through from the door for the c/l and eleccy windows if you have them !!
these wires are tight and after a while of opening the door many times the wires are so short they eventually snap or break ...
garantee this is whats happened on yours mate (check the wires on door that doesnt work)
as will be this one that needs sorting
done a few of these over the years including my own old zafira
hope this helps and if you need a hand let me know !!
wiring plug you need to look at will look similar to this one below !!!http://media.photobucket.com/image/zafira%20door%20wiring%20fault/jalfrezigazee/zafira/24062009.jpg