1. Lower the window
2. Remove long thin pillar covers on left and right side of window frame by pulling gently yet firmly until snaps release.
3. Plastic panel covering inside of hatch will now pop off. Remember to remove strap screwed into the left side of the door's interior.
4. Remove the large metal panel held by hex headed (10mm) sheet metal screws.
5. Raise the window so you have access to the innards of the door.
6. From inside the car, find the cable that runs from the latch at the bottom center of the door up to the lever that pulls the cable when you pull the handle from outside the car.
Here's where you find out what the problem is. The cable may have come out of place at either end, the cable may have frozen by rust or dust, if the cable works perhaps something is wrong with the mechanism that goes form handle to lever or maybe the latch itself has quit working.
Once you've diagnosed where the problem lies and have fixed it, just reverse the order from 4 back to 2.
Source: Source: Son and I in the driveway