I have the book that came with this early 70's unit attached to my
mercury 115hp outboard. Well it's the book for the entire outboard
system. It's one single pump that works both hydraulic shafts to tilt
or trim the motor.

The book says virtually nothing about the wiring, and the wiring on
this thing look like a rats nest. Before I take it into the shop to
see if they can "fix" it, I'd like to make sure the wiring is correct
(given the spices and secondary wires running from a toggle switch).
I'd hate to take it in and have them charge me a hundred bucks to say
"it works fine".

Here's a url to a picture of the unit in question.

http://oskyindians.com/tilttrim.jpg

Lemme know if I can provide any further specifics that might help
identifying how to wire this thing up correctly.