Odometer problem
 

I have a 1999 chev. trailblazer and my odometer comes on and goes off, Sometimes when it's off I can open the hood or the hatch and it will go on but it will not stay on? What the problem?

You may need to have your truck scanned with a full feature scan tool capable of communicating with the various serial bus devices in your truck (IPC & BCM especially) to read the Uxxxx codes that may or may not be present.

If there are no communication codes (Uxxxx) present in any of the serial bus devices, the problem likely lies within the cluster itself. Some have opened up the cluster and inspected the solder joints for cracks, resoldering them as needed and solved this problem. Others have not been so lucky and had to replace the cluster.

I had the same problem my 98. My odometer was on the fritz, but when i tapped on the dash it would go back to normal. Eventually it stopped working all together. I ended up buying a used cluster and putting it in so it would pass inspection.