Yesterday (first -4 C of this winter) drivers door started not to open. Was picking up daughter from kindergarten, the temp was in the positives, so its not like something broke because of the cold. I can hear the central lock mechanism inside the door working while using the fob, also the mechanism unlocks when I pull the handle from inside if the inside door lock button (near gear shift) is used. Also inner handle is a tad loose at the end of travel, but that might just be due to wear and tear.

 

Tried the banging on lock method while using the fob, no bueno.

 

Anyone had a situation like this? Thanks for your input.

Yes, it is quite common fault. I would start with pulling the rubber boot between the door and car body and inspect the wires for damage, if the wires are OK then you may need a new latch mechanism.   

If you can hear the mechanism moving, then possibly it is loose and not engaging.  Or is weak and not moving fully, could try a squirt of WD40

 

Otherwise as already suggested, you need a new latch mechanism, or the wire has broken (usually in rubber bit by door hinges).  Roomster wiring seems to be weak by the door hinges, and wires often break.  I had to have a new tailgate wiring loom on mine.