I'm trying to fix a few issues with a 92 D250 automatic I got a few weeks ago.

Issue I'm having is with the speedometer and odometer. I tried to fix it but no luck.

I replaced the gears in the odometer but it still didn't fix it.

Few thing about this truck.
1. Overdrive not working-has a manual switch for it that works.
2. The VSS was tested, works, no issues.
2. While replacing the gears in the cluster I noticed a wire that runs direct from the odometer/speedometer to the ECU. What were they trying to do with this?

Any ideas?