posted 05-14-2013 01:13 PM ET (US)
In TRIM circuits, the usual color coding is as follows:BLUE = the UP circuit
GREEN = the DOWN circuit.
This is memorialized by the memory aid that BLUE skies are UP and GREEN grass is DOWN.
A conductor with RED insulation is usually carrying the positive terminal of 12-Volt power.
A conductor with BLACK insulation is usually carrying the negative terminal of the 12-Volt power.
The typical operation is apply 12-Volt positive current (RED) to the BLUE to move the trim up, and to apply 12-Volt positive current (RED) to the GREEN to move the trim down. Usually a relay is used to operate the trim motor; the remote controls operate the relay.
An original OMC service manual for the outboard engine from that era should give you the wiring diagram and details of the wiring arrangement. The trim circuit itself is rather simple. You ought to be able to deduce the function of each wire by carefully tracing it in the engine and cable harness.
I don't have any literature on hand from that era.