Q: I am ordering a new ABS unit. They asked me if it has a short or long nipple. on 1990 Ford Thunderbird SC

Rookie cbe0621eac06868b3efe0d8d1d3611e23c60d3114864ea2ec19a68cfbd3eebab
How can I tell which one I need?
(1) Answer
That is a very expensive repair. Why are you replacing the ABS unit. What are the trouble code/codes related to the replacing of the ABS unit?