Speed sensor on Trans, or buffer behind dash... OR, any broken wires in this circuit. Very common problem on this and many other vehicles.
Broken cable?
my Chevy blazer power seat on my 1996 Chevy blazer isn't working
I believe that the first digital cluster on a S-10 Blazer was in 1989.
rpm and speedometer gauges not working 1995 Chevy silverado 2wd
Left side of the where the speedometer is there will be a panel you can remove and there will be where the fuses are
the blazer was stoped being produced in 2005
If the speedometer is not working but the odometer is, I would suspect the dash cluster is at fault. If both speedometer and odometer are not working I would suspect the speed sensor on the transmission is at fault.
If the speedometer is not working it probably needs a new speedometer cable. If the speedometer is actually broken either take it to as speedometer repair shop or replace it.
check ground first
If all the windows quit working you need to look for a blown fuse in the fusebox.
It died of Chevy Envy
i had this same problem, it was the headlight switch, cost about 30 bucks in a 2002. it also messed with the navigation system