Your ST might be effected. My 04 Adrenalin was. I was having the CC light Flash when I tried to engage it. When I took to Ford, they tried to say b/c of my oversize tires (265/75R16). I ended up telling them it was a problem on older ones, that there was a recall. So mine might be affected. They then changed the old one out, and put in a new one, and the problem was fixed.
I didn't a letter.