I don’t know what it is called hooks up to my speed sensor but my speedometer works but odometer doesn’t I think this is it but I’m not sure but I want to know what that cable is called

 

Welcome to the forum

What YEAR Ranger, guessing 1995 or later?

In the last 2 pictures you can see the Speed sensor(VSS) in the background, it has 2 wires "red and black", not actual colors just looks that way in picture

That's why speedometer is working because its still hooked up
Odometer uses the same signal as speedometer, and odometers often stopped working because their worm gear broke inside the dash

Article here on fixing that: https://www.therangerstation.com/tec...r-replacement/


Have to say I am not sure what the wire is for, but a good guess is that its from a broken off O2 sensor, the 4 wire round plug is correct for O2 sensor
Look on the exhaust pipe on passenger side of trans for the remaining 1/2 of the O2 sensor that's screwed in to the pipe or Cat converter

Generic picture of O2 sensor: https://images-na.ssl-images-amazon....lZriL._AC_.jpg

Imagine if it was snapped off above the threads

You should have gotten at least 2 codes for O2 sensor issue when that broke off, one for O2 sensor and one for O2 heater
But for sure would not effect odometer

 

That definitely looks like the upper end of an O2 sensor.