69 Mustang FMX gearbox, the black plug contains wires for the reverse lights and the neutral/Park positions.
Just not sure what the grey plug is for, There is nothing on the wiring schematics that I have.
there is continuity at the plug in all positions except for the Park position,
so not sure if this for another option on another model etc
![Image](http://i968.photobucket.com/albums/ae164/lhellyer69/IMG_20180813_121451_zpsgrmy8uii.jpg)