The wiring color code is similar to that used in the PLC control industry.  Once you get it figured out you are on your way.

The solid yellow line, and green line with trace, are either HNVI lines, or they are the start/run lines from the ECM.  In late model rangers the start/run lines were controlled by the ECM and had a nasty little habit of shutting down on you after a few seconds.  This was due to a routine in the ECM that looked for engine oil pressure sensors to kick in.  If it didn't see this signal it shut down the power to the engine to protect it.  You have to use an alternate signal, ahead of the ECM to circumvent this routine.

Definitions
ECM=Engine Control Module
HNVI=Hopefully Not Very important
PLC=Programmable Logic Controller