I live in Florida and I have a Hurricane sliding door there the lock has failed. I thought that this would be an easy thing to replace, but when I removed the screws to take the lock out, there is a metal bar behind the lock that prevents the lock from sliding down or up (I had to force it to where it is now). The metal bar probably goes up the whole length of the sliding door. I think that the only way to fix this is to remove the door from the track, lay the door down, loosen the bottom bolts then and remove / angle the side out. (I had to do this to replace the rollers a few years ago).
In order to replace this lock, I needed to take the door off the track and then dismantle the aluminum frame with a block of 2x4. Once apart, I unscrewed the locking mechanics and then rotated the lock 90 degrees inside the aluminum channel and slid it to the top. (It would not come out of the bottom.) To replace the lock, I followed the same process in reverse.
It's a shame that the whole door had to come apart to replace a $12-13 part. But I am glad it is done. If pictures are needed for someone else, I will be more than happy to post some.