Used l/h (passenger side) internal door latch mechanism, MX-5 & Roadster mk1, 1989 to 1998.

If your door won't unlock, this is the most likely culprit.  There is a small spring that breaks or comes off and stops the mechanism from returning to the rest position when the handle is released.

Note that we also sell the spring on its own now.

UM00262. NA0159310B.