1984Mustang1989Engine

i have a 1984 Mustang convertible with a 1989 EFI 5.0, automatic, won't start, the starter is fine, battery fully charged and just put in a new starter solenoid literally ten minutes ago, when i turn the key fully a red light that says brake pops up, what's going on?

Boss_Hotrod

Well what else happens? Does the starter click or anything? do you have fuel pressure? Check the other tread for a starting issue. I told a guy there how to check for voltage to the starter.

1984Mustang1989Engine

starter does not click, but when i touch the cable coming out of the starter to the positive battery cable it started trying to crank without the key in the ignition

mattdel

You need to see where the power trail is ending.
The starter solenoid has 3 posts on it. 2 big posts, and 1 small post.
The big post with the cable leading to the battery should have constant 12v(14ish if running)
The other big post will have 12v with the key in the Start position.
The little post is the ignition switch signal telling to solenoid to divert power to the 2nd big post.
Make sure that you have 12v coming in through that little wire while a friend holds the key in the start position.