1996 Ford Ranger Odometer problem

Electrical problem
1996 Ford Ranger 4 cyl Two Wheel Drive Manual

I have a 1996 Ford Ranger with an odometer problem. I replaced the instrument cluster and it worked briefly and then quit once again. I went to a local AutoZone to see if there was perhaps a sensor that was the problem, They told me it used a cable, but when I replaced the cluster there was no attachment for a cable that I was aware of. The speedometer works just fine, at this point I am stumped here. Any ideas? Any help would be appreciated. I did notice that in an earlier post about having to drop the fuel tank to replace the pump, way to much trouble. Simply take the 4 or 6 hex bolts out of the bed and get a friend to help lift the bed off the frame and there she is, easy to get to. I have had to do it this. The bed is relatively light but kinda bulky.