A quick picture of the harness for my kit. Obviously the module isn't plugged in here.
Left to right:
Red wire without Fast-on terminal: Module ignition. Wire this to a key on ignition source
Red wire WITH Fast-on terminal: Module message selection. Leave this unattached to the relay base to use the E38 message set. Connect to position 8 to use the E40 message set.
Right side small red and black wire with terminals: These will pin into the factory ECU where the CAN wires normally go.
White connector with red and black wires: This will connect to the other white connector pictured. The CAN wires from the ECU will be de-pinned and placed into this connector.
Red connector: This connects to the DLC of the GM engine. If the end user wants they can hard wire this instead of plugging in. There should be no need to connect to the GM DLC as the module will allow the GM PCM to be recalibrated through the existing vehicle DLC.