2002 Blazer Service 4WD indicator

Any body know how to diagnose? Light come on after driving for 20-30 minutes. Will reset after turning off engine. Once light comes on unable to switch between 2 wheel and 4 wheel modes. Again turn engine off and on things work for a while. First thought is control switch on dash anybody have any other thoughts? Thanks.

Someone with more knowledge of the 2002 model will have to help, but since no one else has input at the moment, I just had a few things to say.

My GM service book for '98 shows the systems with the Service 4WD light and the systems without the Service 4WD light. For the systems without the Service 4WD light, you can jump a connection in the diagnostic connector and have any troubles codes for the 4x4 system flash on the 4x4 push button systems.

But for the systems with the Service 4wd light, it does not show this ability. But instead, it instructs that a scantool is used to read any stored trouble codes.

I would not be likely to believe that your push buttons are at fault. When the Service 4wd light comes on, the system is likely locking out the 4x4 system, resulting in the push buttons not working. So I don't think the fault is the push buttons themselves. However, further diagnostics is needed.

Hopefully somone will have more help.