The fix was relatively simple. Removing the old adjuster housing was a matter of popping out the plastic brads that hold the inside and outside sections together, removing the inside section and the actuator, and snapping off the tabs that hold the outside section to the track. This is not difficult but is a destructive process so make sure the new housing is the correct one. The new housing (with the actuator) is then installed using the torx screws provided, which replace the original brads. Be sure you have the actuator correctly positioned so that it functions properly. Noting how the actuator was positioned in the old mechanism is a good idea but it is fairly intuitive.
The only tricky part of this job is that the screws are torx. You have to have a 1/4" torx driver (screwdriver or in my case a torx socket) to complete the job. I recommend the socket because the screws must be driven into the plastic of the inner secton of the actuator and it takes a fair amount of grunt. As a preventive measure I did both sides.