Having trouble with the headlights and taillights on my C-8000. Basically I can not get them to work. I have a new headlight switch and all of my fuses and circuit breakers are good. My turn signals work, dash lights work, marker lights work, and interior dome lamp work.

Anyone have any clue where I could start to look for the problem?

 

At the battery. Move along the wiring till you hit air, then figure out why.

Or, start at the light and move backwards till you hit juice. You'll find a gap either way.

Check your grounds also.