1973 Dodge D-200 Time to hang a new harness

and check the bulkhead connectors through the firewall
but it back together with dialectric grease
often one of the spade terminal clamps is broken or bad solder job (if soldered and not jist crimped- I do not trust just crimps
do the amp gauge bypass and headlamp relay mods
eliminate high current through headlamp switch and ignition switch with relays
check all the grounds and clean
find the reason (high resistance) (alternator or other short of currant leak)