Yesterday the 4x4 button on my 99 blazer was working fine. Today when I started it up to leave for work I got a quick red light and then no lights at all. It is the 4 button switch and does not light up except the fast red light as I start it. Luckily its in 2wd. I have another switch I'm going to see if that solves the issue but my luck probably not. Is this a TCCM issue? I'll be doing wheel bearing and ball joints on Friday so I'll look more into it then. Any other possibilities?

 

probably vacuum related