How do I fix the Passenger Door Opening mechanism for the Exterior of car?

There's usually a rod, on the inside of the door, that goes from the handle to the latch. This rod is held in place by plastic clips that often break and fall off allowing the rod to fall down inside the door. You'll need to remove the door panel to gain access to replace the clips and put the rod back where it belongs so the door handle will open the door again. Hope that helps! Jim

What Jim said; If your not body work or mechanically savvy look up door panel removal for your car on U-tube as there are often hidden bolts or screws holding the panel on, once the panel is off there's a piece of plastic (a weather guard) stuck on the door, peel back carefully because your going to put it back on, the black glue is nasty and will get stuck to everything if your not careful, just peel back enough to follow Jim's instructions above.