The sauldering on the board behind the lighted display has come loose. You need to get it resauldered by someone who knows instrament panels, or it will do more damage than good.
My 92 Blazer S-10 4x4 lost all the lights on the dash. Local dealership quoted bet. $700 & $900. My mechanic took it out for me ($100), I shipped it to a guy in Canada who repairs these (he charged $125), the my mechanic replaced it. Been working perfectly ever since. I drove the car without the dash with no problem but the remove & replace only took about 4 days anyway. The guy in Canada in online, look up dashboard electrical repair.
If both the speedometer and the odometer work on and off, I would blame the vehicle speed sensor. If only the speedometer is acting up, I would blame the cluster.
There is a problem in the distributor. Either the pickup coil or the ignition module are defective. It may be cheaper to purchase a remanufactured distributor.
The fuel pump for the 1990 full size blazer is located inside of the fuel tank. If this model does not have an access plate in the floor of the blazer then the tank will have to be removed to get to the pump.
A 1996 Chevy Blazer Does have a transfer case IF it is equipped with 4 wheel drive
HACKED
I believe that the first digital cluster on a S-10 Blazer was in 1989.
you need a new instrument cluster about $350 same happened to mine.
If nothing on the dash (instrument cluster) is working, I would suspect the electrical plug in back is disconnected.
There is no odometer cable. The cluster is controled by the PCM and is fully electronic. www.trailvoy.com All the answers for your Trailblazer!
Remove the two screws at the top of the instrument cluster. This will allow you to pull out the entire bezel. Pull out the bezel, and pop the switch out from the bezel.
It sounds like a wiring issue. There could be a loose wire on the instrument cluster, on behind the fuse block.
Fuse panel should be located on the drivers side between the door & the instrument cluster. There is also 3 relay switches located behind the back panel of the glove box.
In our 96 Blazer S10, it was behind the radio. We had to remove the radio to get to it.
When my 96 S10's ignition switch went bad my cluster would act "crazy". Needles bounced back and forth while trying to start. It drained my battery and had to jump start. Also ended up replacing the ignition key tumbler twice in it too, but it was the switch down low on the column that made the cluster screwy.
I would first recommend getting the Chilton manual. I did the heater core on my wife's 96 Blazer. It is a very involved process and should only be attempted if you are a fairly knowledgeable mechanic. You have to remove the instrument cluster and drop the steering column to start. The Chilton manual covers this fairly well. Dennis
faulty circut board replace it
its inside the distributor.