Gauges work, then don’t, then do

[72RoadrunnerGTX]

The horn works, as it always has.
The ONLY thing that never worked on this car in the 12 1/2 years we’ve had it was the key buzzer.
After getting the ignition switch and key lock installed, the buzzer worked for the first time ever.
It stopped working when the no-start(nothing) continued, like immediately after the key was turned, even before the ignition relay and NSS were changed out.
My thought is that the small black wire that was inadvertently left in the harness(that shouldn’t have been there) may have caused this issue.

If the horn works, the buzzer has power, issue is on the ground side of the buzzer circuit or the horn relay/buzzer.
Not related, leaving the small black wire on the later replacement ignition switch lead in place won’t do anything until the first time you start the car with the lights on, will then blow the dash illumination light circuit fuse. Nothing to do with key-in buzzer. You could also jump the two small red wires in the ignition switch connector, see if it buzzes with the driver’s door open. This would isolate the key-in switch itself.