How to repair tailgate lock on 2003 Ford Focus?

The tailgate lock stopped opening with the push button. With a multimeter I measure a 12V one second long pulse on the lock connector every time the button is pressed. I removed the lock to repair it but I can't figure out how to open the lock. I pried up the plastic tabs but it don't come apart. I don't see rivits or screws. By lock I mean the latch, not the key cylinder.

Questions; how can I disassemble the lock? Is a 12V one second pulse normal, or should it be longer?

Curt
February 2009