If tightening them helped, I'd consider loosening them enough so the box wiggles and then tightening them again, just to make sure there is good contact.

 

Those lights are supposed to come on momentarily on startup. If not that, the connection to the EBCM might be loose.

 

How old is the battery?

 

Ok, so it has been a while but after i left, maybe an hour later, the owner went for a drive and all the issues resumed. It dings random amounts of time (i believe it to be the bcm booting among other things). There is very obviously a power/grounging issue to more than one component. The guages on and off (lights and all). I am COMPLETELY lost at the moment. Every connection i check has no corosion, all fuses are good, battery is a year and a half old, clean, and passed a current draw test at a nearby shop. I dont think tightening those bolts did anything, i think i just didnt happen to encounter the issue while test driving. Not intermittent but it varies in sevarity and obviousness

I would like to reiterate that it seems to be made worse/caused by vibration as i have 0 issues at idle as i am able to get codes and whatnot ONLY while sitting in the driveway. If i even rev it though, it ****s the bed.

 

Then disconnect the negative terminal at the battery in the rear spare tire well, then undo those 4 bolts to wiggle the fuse box apart and check for bent or pushed in pins , a little dielectric grease and reassemble the fuse box , tighten those 4 bolts past the clicks until they are good and tight. Check the master fuse and ground in the spare tire well , then reconnect the negative terminal, inspect for a crack in the negative clamp.

 

So something is loose. The fuse box bolts are the prime suspect; tighter than " they seem tight to me". Then every connector, they all have pins that can get bent or pushed out the back. Then all wires can get frayed or burned.

I would loosen the 4 bolts in the fuse box, then tighten them back down using the gorilla forearms ti ensure that all of the 100 or so blades make full contact with their slots. It usually takes hearing 2-3 clicks.