Hi my name is Wes I drive a 1987 K5 here is my issue, all interior lights were working great got in it this morning and turn my headlights on and my dash lights do not come on but the courtesy light underneath the Dash comes on and stays on when the headlights are on I'm thinking its a bad light switch just would like some more knowledge as to why this could be happening

 

I was able to some more investigating today, a buddy of mine noticed I had brake lights but no tail lights, so I pulled out my Haynes and started studying the schematics and was finally able to isolate my problem. One of my tail light filaments blew also the 20A fuse for the Tail lights/courtesy light was blown as well so easy fix this time replaced bulb and fuse and good ole chevy is ready to hit the streets again.