Electrical System Flunked

Hard to say, especially without photos. "It might be" that all of that could be fixed, but if the wireing is a victim of hacks, smoked, melted, and corrosion, then yeh, rewire. If you can't fix what is there then it might be a big job for you to tackle

So far as the separate push button, the annoying 74 only U.S. Federal "safety" "seat belt interlock" might be to blame.

So start right there. Look for the reset button under the hood on the driver's fender panel. There should be two "yellowish" wires. Splice them permanently together.

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You need to scare up a factory shop manual, and unfortunately, MyMopar which has free downloads of many of them, only has up through 73, which has a number of differences