4 Way Flashers Not Working
 

ok, new issue.4 way flashers. Don't work. Is it run off the same flasher as turn signals? I have a light bar/strobes, just irritates me the 4 ways don't work....thoughts..DD

I moved this into a new thread as it is a separate issue.
Would be great if someone could post a schematic diagram for your truck.
By chance does your owner manual show the under hood relays for flashers/signals?
If the 4 ways & signals are tied into one flasher, could be the wires into the 4 way flasher switch or a separate relay? Check the fuse for it?
I'm sure the guys will chime in with some more ideas on this one as well.

Year, make, model?

According to his profile it is a 1997 GMC K3500

If your brake lights are working, more than likely your turn signal switch is bad.