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The block on the firewall is referred to as the "bulkhead connector" the 3 plastic connectors are keyed, and all 3 are different.
Go to mymopar.com there are free downloadable factory service manuals and wiring diagrams.
Classiccarwiring.com has wiring diagrams that are laminated and color coded. Best 20.00 you will spend.
If you need to clean up wiring american auto wire is a great source
American Autowire: Wiring Harnesses, Accessories, & Parts for GM Restoration, Modified Restoration & Custom Street Rod | American Autowire
if you need to replace terminals be sure you get the correct ones. There are also single wire and double wire terminals, and various sizes from 10 awg to 20 awg. And in the case of terminals size does matter.
also terminal cleaner Deoxit is a great product.
What ever you do, DO NOT use sandpaper on contacts, it removes the plating and creates a place for corosion to start. A stiff brush, Deoxit, and a pencil erasure is all that is needed.
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