[Ski-me]

Does your cruise control work and hold steadily? Did you follow the twisted pair all the way up to be sure it wasn't melted/shorted out somewhere?

Those twisted wires go up to a DRAC unit, which then interprets that signal into pulses for the speedo, cruise, computer and ABS. I don't recall where the DRAC box is "factory wise" but I think it comes in on the passenger side. Whitish clear box if I recall correctly.

You might be able to go out and get a replacement in the junkyard but each DRAC is set up for a specific tire/axle ratio combo.