Get a Service Manual.
The pdf scans here will at least get you started in most cases.
MyMopar - Mopar Forums & Information - Service Manuals
Go to the back of the electrical section and you will find the wiring diagrams.
Many TSBs can be found in the
The 1970 Hamtramck Registry Library Page (1970 - 1974)
And lots of Chrysler Tech tips here
Master Technician Service Conference - Chrysler's Training for Mechanics
Including a couple about reading wiring diagrams.