Yesterday, for no apparent reason, I could no longer open my 1992 745 Wagon tailgate after unlocking the central locking system. One minute it worked and the next minute it didn't. So today I read up on this problem in the FAQ and tore into it. None of the solutions listed applied, so I was stumped. This was a big deal, because my rear lock cylinder had died of terminal corrosion before I acquired this car and the only way to open the hatch was the inner and outer handles and the inner one was quite inconvenient.

After removing the latch mechanism and the inner handle mechanism, I found an "empty" plastic push-rod anchor on the latch mechanism. Turns out this was the culprit, because the lock solenoid had become disconnected from the latch. I have no idea how this could have happened, unless someone had previously neglected to snap the push-rod anchor clip around the push-rod, allowing the end of the push-rod to work itself out of the anchor over time. I didn't see this in the FAQ, so perhaps it should be added. It's quite difficult to see how the mechanism works without removing it, which is why I didn't see what was wrong in the beginning.

While I was in there, I also unscrewed the push-rod between the outer handle and the latch mechanism a bit to lengthen it, because the latch had been operating very near the limit of the handle's travel, Now it works about mid-travel.