I went to my local mechanic for the same seat problem over the weekend & it would cost like $90 labor + parts for him to take the seat out & check what's wrong. I was told to come back during week days so he can order parts form the stealer too.
I decided to search in the internet & end up here. I was lucky enough to find the white cap that was in my garage's workbench's cabinet. All it takes is 10 min. & a penny coin to screw the white cap back to the passenger seat & BINGO, it works!
Thanks, guys!