sounds like you need to replace that piece i had some work done on my car and dealer broke that part when the put it back it would say i was in neutral or reverse when i was in drive. I have taken it apart several times. you have to remove the leather shift knob first by shifting down to drive or 3 gear squeeze knob in and pull up hard on knob dont knock yourself out doing this

after that try slightly push back from the area where the 1 gear number is slider then pull up carefully should pop out there will be a wire attached to it thats were it lights up during the night when your lights are on. I dont know how much that part is sorry. Hope this helps