I had the exact same problem you do. The car had front and rear openings and the bottom landing was the only rear. When it came to the landing and opened the door it would feather on the limits and close and open erratically. The mechanic that had the route thought it was the edge so I came and replaced it without troubleshooting, Problem still persisted. I then opened up the car top door board and found a blown 1/2 amp fuse. replaced the fuse but still had issues. I readjusted the pots on the card and the doors magically started to work again. Its been running non stop for almost a year now.... I dont know if there is a bad tracer or a bad component on the board, sounds like you had it repaired and problem still persisted. I do find it interesting that the additional landing board plays a part in the problem. My old boss used to install these controllers years ago and has quite a bit of knowledge on them. I'm going to ask him about it and see what he says. Good luck out there.