80's/Early 90's movie about a woman locked in an attic

I remember my mom watching this movie in the early 90’s and it was in color and the characters seemed to be dressing and wearing hairstyles from from the late 80’s or early 90’s.

I don’t remember a lot about the movie except there was a young woman with dark hair who drives this really fancy vintage red car that possibly also had white accents on it. This car was from before the 80’s, possibly a 60’s or 70’s car. She goes to visit a blonde woman who is a friend or family and they go up to look at an attic bedroom in the blonde woman’s large older home and the blonde woman states, “you go ahead first” and then promptly locks the dark haired woman in the attic room. The room has a window that is completely boarded up, a bed, and I remember there being a wheelchair in the room as well. The blonde woman and a man that I assume is her husband come up to the room to visit the dark haired woman at one point. There were also children living in this house.

I can’t remember anything else but maybe these people wanted her car and that’s why they locked her up in the attic.

Might be this, there are a couple of versions of it.

Flowers in the Attic