65amp wiring/trouble shooting

First identify and fix the problem.
One common problem on especially in 70s models is a leak: Redfish (who worked at Chrysler dealerships) has mentioned that
https://www.forabodiesonly.com/mopar/threads/ammeter-gauage-for-74-duster.498859/post-1973577130https://www.forabodiesonly.com/mopar/threads/electrical-gremlin.499116/post-1973580394A lot of people think the ammeter is the problem. Sometimes they are, but often they are not. When there is excessive current in the battery feed line the connectors got hot, very hot.
In this case the ammeter needle position when it occured and afterwords identifying all the overheated sonnectors will be the clues in tracking down the source of the problem.
Some melted wire connectors shown here, including a ammeter connection which we know exactly why that happened.

If your car has one of the Heavy Duty Alternator options, then yes the wiring for that part of the circuit is a bit different.
One version, '73 B-body with 60 amp Chrysler alternator shown here. Seems similar to the A-body version as documented in the late 60s assmebly drawings.

There was a different version used with rear window defrost grids. How rare is electric rear defrost?

1975 and 1976 each have their own unique wiring for the power feed.
https://www.forabodiesonly.com/mopar/threads/ignition-help-needed-stumped.499412/post-1973585053