ok I'm stumped
 

when I purchased my blazer I knew the speedo wasn't working, so I figure no problem, I've replaced the VSS on my other 2 so why should this one be so different

wrong..

first thing I did was change the VSS, still no speedo or odometer, then I removed the cluster looked for bad solder connections resoldered a few, reinstalled it, same no speedo or odemeter.

so the whole time the transmission shifts prefect, I went out and tested the cruise control it's working great, so the vss has to be working

am I looking at a bad stepping motor in the dash for the speedo??

what year blazer? it could also be the connection at the trans case, unless thats the VSS ur talking about. if not, try there......its a boxy looking thing that has ur speedo cable attached to it thats attached to the trans case. if its broke or sticky ur speedo or odometer wont work.