I have a 98 blazer. When I start the vehicle headlights come on tail lights come on but the instrument panel does not work I could drive down the road and no speedometer and no tack gas gauge don’t work radio doesn’t work cigarette lighter doesn’t work dome lights don’t work but when I turn on the headlights everything works that means that there is something amiss with the wiring and would like some Input on what it might be

 

It sounds like you could have a problem with the ignition switch. Check out the following link --> Anatomy of the Ignition Switch. It should have all of the information you need to test the ignition switch. I just added some new information towards the bottom of that tech article today that makes testing three of the ignition circuits quite a bit more user friendly. If you have any questions, please post up! Let us know your results as well!