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.
The 2001 Chevy Blazer does have an ignition security system that is controlled by the computer in the vehicle. The light might come on because of an error that is coming up in the computer due to a key problem or an ignition problem. This is a common issue with the 2000 and 2001 Blazer.
There is a separate motor that runs the odometer. It is not running for some reasson. TAke it to a speedo shop.
YOU WILL DIE! have you check your IAC ??
The blazer must be in park for the rear hatch button to work. If you have the blazer in drive the button will not open the hatch unless it is in park!!! If there is still a problem maybe try checking the fuses! The actuator could be broken in the rear that releases the window so you can open the back. This happened to my 2003 Blazer and my neighbor's 2002 Blazer. By removing the back panel (high likelyhood the panel will break when you remove it) and replacing the actuator that could solve your problem. Both I and my neighbor would have had to order the whole actuator in order to replace the tiny plastic piece that broke. Instead we drilled a whole and rigged it with some tough wire. Works now but we both have broken back panels...even the dealership broke one. Good luck. SEE RELATED LINK for 1997 Blazer
The check gauge light on a 2000 Chevy blazer could be several things. The oil could be low or the other fluids may be low. Take notice of all the gauges. One or more may be out of its normal parameter notifying you there is a problem.
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.
at the tail of tranny
If it is electronic (not cable driven) and both the speedometer and odometer are not working I would suspect the VSS (Vehicle Speed Sensor) is faulty. The VSS can be found on the tail end of the transmission. If only the speedometer doesn't work I would suspect the dash cluster has to be replaced with a new or good used one. Really need to know what year S10 Blazer you have.
Broken tooth in speedometer head. Replace speedometer head
Need to know what is wrong with it. If both the speedometer and the odometer don't work, I would suspect the VSS (Vehicle Speed Sensor) located in the back end of the transmission is bad. If only the speedometer doesn't work, I would suspect the instument cluster has to be replace with a reconditioned one from your local Chevrolet dealer. Contact a dealer for a price.
faulty circut board replace it
It has an electric speedo and has a speed sensor.
Broken cable?
Speed sensor on Trans, or buffer behind dash... OR, any broken wires in this circuit. Very common problem on this and many other vehicles.
Left side of the where the speedometer is there will be a panel you can remove and there will be where the fuses are
i had this same problem, it was the headlight switch, cost about 30 bucks in a 2002. it also messed with the navigation system