I have a 1999 chevy blazer and the 4x4 service light comes on and off and the same with the light on the dash that lights that tells you what stage you are in if you hit a bump in the road it will come on and off
thank you for your help

 

Have you had the TCCM scanned for stored codes. If the 'Service 4wd' light comes on, the TCCM will store the code related to the issue it has experienced giving you important direction into the problem. Once you get it scanned, post up the codes that were present.

There is also a lot of information in our Tech Article (DIY) section that you can read through to help yourself out. If you have seen the 'Service 4wd' light come on, then you have the 4-button Auto4wd NV236 transfer case so you can look for NV236 specific threads in the Tech Article (DIY) section along with a quick read through the other generic 4wd related threads in that section.

Corrosion at the TCCM is a common problem with the s-series vehicles. The TCCM is located behind the front passenger kick panel, just ahead of the front passenger door. Remove the panel, then remove and inspect the connector(s) at the TCCM for signs of corrosion. Clean up or replace terminals as necessary.