The Digital Matter iButton Reader has the following wire colours:


      

Red    
iButton Signal Line
Black
GND
Green
Green LED
Brown
Red LED
Yellow
LED Negative


The G62 harness definition can be found here: G62 Harness Colours



The brown and green wires on DM harnesses have 1000 ohm resistors connected. 


For a simple implementation (read driver ID, LEDs won't light up) connect the following wires:


G62
iButton    
Brown (iButton input)        
Red 
Connect to G62 or vehicle GND
GND


To control the LED, the Switched GND output of the G62 can be used to provide a GND to the LED negative (yellow) on the iButton


In this case, connect the following:



iButton
Brown (iButton input)  
Red (signal line)
G62 or vehicle GND
Black (GND)
Positive on vehicle
Green or Brown
Green (Switched GND output)
Yellow


Depending on parameter setup, when the switched ground is on (provides GND) the LED will turn on.