Speedo cable problem 72 challenger

[Stu]

Can anyone out there tell me what the sender unit attached to my speedo drive does on a tf 904 trans in a 72 challenger.has a single wire attached to it

Thanks

 

[72RoadRunnerGTX]

It’s a speed switch for the NOx control system. California cars only in ’72. Unless the other components are present and functional, it can be omitted.