What is a wiring schedule? 

Basically the wiring schedule will specify the wire reference number, type, color, size and number of conductors, length and required amount of insulation stripping. And this is not a diagram but a reference to the conductors that were used for easy identification in the circuit. In complex devices, you'll also find a table of interconnections that gives the start and end reference points for each connection, as well as color, size, identification markings, and other important information.