I think I messed up. After I cut 12mm of the cable sheathing, there's a total of 21mm of drive cable visible (from the top of the sheathing where it was cut to the bottom of the drive cable. Does that sound right? If I put the remaining sheathing on with the metal grommet, there's still lots of drive cable exposed. What gives? Also, before putting everything back together, I tested the headrest motor with the seat switch, with the backrest back in position. It only stays on for a few seconds, then stops (both ways). Is that normal?

 

Never mind. I re-measured, put everything back together, and miraculously, it all works fine now. Strange, but I'll take luck over skill any day!

 

Sounds to me like you did things right!

Doug