Swithes from 2 wheel drive to 4 wheel drive

:frown: The indicator lights on the dash switch from 2 while drive to 4X4 automatic all by it'self. The mechanic is having trouble finding the problem. It doesn't actually switch but the lights do and once in a while the service 4 wheel comes on. Any ideas how we ca solve this and fix the problem?:frown:

Welcome to AF.
What year and what transfer case?
Need the no off of tag on rear of transfer case.
Does the shift buttons on dash have a auto button or just 2 an 4W and low?

It is a 1999 Chevy blazer. I don't know the number off the transfer case. The Blazer is at the Mechanic now. They can't seem to find the problem.:banghead: It does have a 4x4 auto button as well as 2hi, neutral, 4hi and 4 low. My Mechanic only uses GM parts, he's a former mechanic at a local dealer.

If the auto button you have a 236 transfer case.
With a Transfer case capable scanner there is a lot of function test and info in the transfer case module. Even a light turn and off test for the switch.
A good time to run the scanner on it is when it does it.
Also a good time to service it with the new type GM blue transfer case fluid.
Let us know how it goes.