1969 2dr hard top monterey 3spd auto 390 2v

my son and I purchased this car from the family of the man who purchased it in august 1969, the car has set for10 years in the oldest son' attached garage. although i have been an electronics tech/engineer for 27 yrs and spent about 10 years in the oilfield before that, but I am not a mechanic. This will be my sons 1st car and he just loves it. I have purchased the Ford shop manuals, but was very disappointed in the almost complete lack of the wiring details. Where can I find these documents, the shop manuals do refer on multiple occasions to "Wiring Diagram Manual, Form 7795P-69". Where do I get a copy of this manual? I am tracking down a 4.5 current draw in the Monterey and could sure use the wiring layout. Thanks