While I was poking around behind the kick panels I looked at ground wires and everything seemed OK. That doesn't mean they ARE ok but... ugh. I don't know what I'm doing or what I'm looking at. Thankfully the truck has never lived near the ocean or in a rust prone area. It's been in the Sacramento valley all of its life.
I'm not about to tear in to the dash again to hack in to the wiring harness and ground things again. Those wires are too delicate and I'm not confident enough that I'll get things right without making more trouble.
I agree 100% that the problem is upstream of the instrument cluster. Should I replace FLs or look at them and make a mean face? Things 'appear' to be OK. Clearly they are not.
Would photographs of anything help diagnose this one?
On the ground wires, "looking OK" means nothing. Unscrew the screw holding the wires to the sheet metal, wire brush all the connector surfaces, use some sand paper to get the paint off around the ground screw hole and then put it all back together. I had a loose ground similar to that that would kill my cruise control if I hit a bump/expansion joint in the pavement when it was engaged. All looked fine, but tearing it apart, cleaning and reassembling fixed the issue.
And try pulling and checking *all* fuses. Inspect closely as sometimes a fuse may only be partly blown. And sometimes, the fuse contacts may be dirty or oxidized and simply removing/reinstalling them will clean off the dirt and make them work. I once had that very problem where I lost all the dash power while driving, engine still was running. This was after the truck had been in the shop for over a week. Pulled over, shut off the engine, pulled and checked *every* fuse looking for the problem one. None found, but decided to start the engine back up and drive back to the shop that had been working on the truck the last week and viola, everything was working.
