Hi! Everyone. I think I can use some guidance on this.
My 1971 stock instrument panel went dark tonight. The switch seems to work since the headlights are on.
This happened a few months ago. This was the short 5A fuse at the bottom of the fuse box. I just replaced it and the problem was fixed.
So, naturally, I went to directly to fuse this time, checked it - it was fried - and replaced it. No light. checked the new fuse: Fried.
OK. May be it was a bad fuse. I picked a new fuse and checked it before installing it; it was fine. Installed it. No light. Removed the fuse and checked it: Fried.

OK. That probably means I have a short somewhere in the circuitry. How do you suggest I proceed from there?

 

First, get yourself a good wiring diagram for your year, in color. Troubleshooting is much harder without one. For what it's worth, the dash lights are all gray wires on my 77. I think that's the same on earlier C3s too, but double check.
Second, has anything recently been opened up in your dashboard prior to the problem starting? In my experience, most of my wiring problems are self-induced (pinched wires when reassembling panels, for instance).
Third, since you mentioned the fuse blew previously but then worked for a time after replacement, you have an intermittent short that has become constant, probably from a wiring harness that has rubbed raw against metal. That means tracing the dash light circuit from the fuse block to the lamp sockets until you find the bare wire that's causing your problem. In other words, pulling apart the dash to examine the wiring harness for cuts. No fun at all, sorry.
You might be able to minimize the work by strategically checking the wiring at points where it runs close to sharp metal areas. My first look would be where the dash light wires exit the loom and plug into the speedo and tach. Those wires just kind of hang down behind the gauges, and could rub against the brackets that hold the speedo and tach. They don't require much disassembly to check either. You just have be able to bend yourself into a pretzel to look up under there.

 

Thank You for your suggestions. Yes, I can't figure any other way. I have electrical diagrams although not in color. But color codes are printed.
I have changed all the bulbs a couple years ago and had no problem so far. So, I know that pulling the dash is no fun. And yes, I believe I must have an intermittent short that became permanent. I am rather tall and the access under/behind the dash is somewhat challenging for me. It is a rare instance when I wish I would have shorter arms. I am afraid I am good for pulling the dash out again. Thanks for confirming my initial diagnostic. I wish I would have missed something simpler.

 

Pulling the drivers side dash pad completely out is the worst repair job that I have experienced on my 73 convertible. This job is horrible unless you are willing and able to remove the steering column. That being said I would first take a look at all the wires on the center gauge console, it’s not to hard to remove. Do a Google Search for the step by step procedure. If you don’t see any frayed or damaged wires, then you could try to loosed the drivers side dash pad a few inches to inspect for damaged wires. Remember the wires are close to 50 years old, and the plastic insulation on my wires are like steel. If you find any DAMAGED wire with the insulation cut or frayed, go to HD and look in the electrical department for Liquid Tape. Make sure to cover everything because while it’s thick, it seems to always drip down on something. If you find a cut wire (should be gray), do a Google Search on the best ways to solider old wires, getting the insulation off is another adventure. Good Luck