Replace all wiring?
I have replaced every wire under the Dart’s hood, and modified the system with relays operating headlights, electric choke, o2 sensor, and charging circuit. The Dash just needed a few hacked up conductors replaced, a new fuse block, and a pair of relays operating the convertible top pump. Also I replaced every brass connection to eliminate any corrosion resistance problems, and installed a new OEM bulkhead connector.
Rear of car is all original, but I did rebuild light sockets clean all lamp housings, remake all grounds, reinstall tail light assemblies with new body gaskets.
The electrical system is now very reliable.
Price a new harness replacement (several sub harnesses needed), and you’re looking at a thousand bucks to do the job in just parts.