Hi Guys i really want help for this issue !

FIRST thing you need to do is to take a look at the ammeter. Particularly the WIRES. If this is the "older" "full current" ammeter using large gauge (no 10 or so) wires, you may be able to modify a 73/4 harness. If it is the "external shunt" ammeter using SMALL gauge wires--perhaps no 18? That is the "later" ammeter, and you will want 75/76 harness "to modify"

There are no free downloads for the 75/ 76 factory manuals. I may be able to scan parts of a 75? I have. The aftermarket manuals over at MyMopar may be "some help" but they are far from complete.

Frankly I would go out and find a paper or digital 75 manual and buy one.

I WOULD NOT ATTEMPT to adapt an earlier harness such as 72 / earlier

Another thing you might "figure on" is to stretch out the old harness section by section, "nail" it down to a board, and carefully lay out all branches. Unwrap the "tape" but tie off the branches. Repair or replace as needed. You can obtain some/ most of the electrical terminals, if the plastic connector shells are not damaged.