I have a 1998 GMC Sierra 5.7 V8. The heat/ac controls don't work, no lights, no blower. When I get in it at start is it may come on for a minute then quit. Also my 4WD indicator lights won't work. Manual says fuse for both. CHANGED FUSE but it's still not working. I was thinking it may be a ground but I don't know where to begin. Or what else could it be?
