I have a '70 grand coupe cuda w/383. A couple years ago I had issues with the neutral safety switch and replaced it outright. Since then the car has been running well. Below I've listed a sequence of things that have been strange involving the electrical system.
A couple months ago when driving for over an hour with the lights on, the lights started to flicker and eventually would completely go out. The car would still drive and ran fine, but the lights would not come back on. If I would stop the car and re-start it, the lights would work fine again.
A few weeks ago I started experiencing an even more odd situation. The car will start right up and I can drive it for 2 minutes or 2 hours, but when trying to start it again the car is completely dead. I cannot even get a click when trying to restart. However, if I jumped the car it would immediately turn over.
Now the car does not have power at all to anything: lights, ignition, horn, nothing. When I put a test light on everything, I have solid power to the starter relay & the starter itself. The main power cable from the battery shows power into what is block #16 on the first block inside of the firewall. I however do not have power to the 2nd block in the wiring harness within the firewall.
It seems like there is power coming into the car, but not allowing the power to go out. Any help and advice is greatly appreciated. I'm totally scratching my head on this one.