A few weeks ago was adjustung the full power screw while the truck was running and grounded a wrench from the fuel shutoff to something...Truck seemed fine except voltmeter(stock) which never worked started flickering. Started it a few times, it seemed fine. The next day turned key and got nothing, no click just the key on buzzer. So I replaced starter contacts, drove around for 2 days no issues. Then no start at bank teller! Trailored truck home and it started a few days later. I replaced the starter relay for kicks. Now still randomly fails to start(nothing no click) and lights get dimmer then brighter. I cleaned the underhood grounds including screws to voltage regulator and that helped some but still same issues.

 

Check the fusable links maybe one is bad and randomly making a connection. They are located near the hood hinge over the driver side inner fender.

 

Thanks, will check tomorrow! Any other ideas?