1998 Blazer, cruise control works, scanner tool shows the speed also. Tach gas temp pressure all work, speedo odo do not, Took the cluster apart and cleaned the connections, any ideas? Maybe they`re just bad?

 

That is interesting to me. When I bought my 98 someone had changed the Speedo. I have wondered why. How I know is the Carfax said it had 115,590 miles when I went to look at the vehicle it showed less mileage. So I asked the seller & he confirmed it had been changed but didn't know why. Mileage on CARFAX was consistent from day one.
So please post what you find.

 

I`m gonna try a cluster from the junk yard