'Modern Family' Star Ariel Winter -- My Broken Family Can't Be Fixed

"Modern Family" star Ariel Winter says she will never have a relationship again with her mom and her older brother ... this according to one of her text messages.

The text -- obtained by TMZ -- was filed in Ariel's guardianship case. She was texting her older brother Jimmy who has sided with their mother in the battle over Ariel.

Ariel, who is now under the guardianship of her sister, wrote, "How dare you say you miss me ... if you really wanted to see anyone and cared, you'd do a 180."

And then she goes in for the kill: "I'm sorry, what we've been through can't be fixed."

Ariel's mom filed the document, trying to prove Ariel suffers from PAS -- Parental Alienation Syndrome -- and their family is being destroyed as a result of the guardianship.