98 3.8 Electrical

Just wondering. Did you hook back up the ground wires that run from the left hand radiator core support around the battery? The medium sized black wires with a white stripe terminate in a round single pined connector.

Did you also remember to reconnect the motor bare motor grounding strap that goes from the left hand motor mount to the body frame?

Also the large main battery ground from the battery negative to the motor itself?

Do you hear the CCRM click when the ignition switch is turned to on?

Here's some more information.

1996+ Crank with no start check list
https://www.allfordmustangs.com/forums/4-6l-tech/336452-1997-mustang-wont-ignite.html