Dash lights will not turn off!! 72 dart

Those can be a mess. I recommend you spend the time to pull that section out and inspect it. Work? You bet. Remember, these originally were installed or replaced with NO cutting. You may not need to pull it ALL out. Pull some out and if you see the "melt" becoming less, try to identify the affected harness colors and purpose by following them to the branch connector. AKA is it the radio, etc. You can tap/ tie/ zip tie unwrapped branches to keep them in proper location. Once you get back to "goo" wire and are convinced there "is no more" further along, then you can splice/ repair / replace wires, etc.

Try to note what you have done so you have some idea as to the cause. AKA let's say there was some sort of short internally in the headlight switch or some such. It would be a shame to repair all that and get a "repeat."