Well, there really isn't a key code. Every lanyard has a unique code in the chip buried inside the snap on black rubber part. Using the proper software, like BUDS, this unique code is programmed into the MPEM or ECU of the ski.
The location of the wire harness to connect to is near the MPEM, top right, a grey 4 wire connector that you have to unplug from a "cap" bus connector and connect the input cable. Older skis did it right through the DESS post. But unless you have the complete software set up, which my guess is you don't, this information won't do you any good.