As the answser above but also could be the door lock gone faulty,
If you unplug one and it works ok its tells me that its the one you unplugged gone down.
Peugeot also suffer the same problems, and they have diddy switched inside the lock assy that die...
Bonus is these are as cheap as chip to get s/h and easy enough to fit.
Hope that may help if ur not sorted ?
AndyG
September 2012