Double K-LINE Adapter
This adapter performs the same function as the switch on many K+DCAN cables. It bridges pin 7 and 8 on the 16pin OBD port to allow full communication to older generation BMW's.
Models such as E46, E53, E39, E38 etc require this to communicate with the rest of the control units. Please advise, if your cable has a switch like the Pro-Cable, you do not need this adapter.
If your car is earlier than 2001 or has the round 20 pin port under the hood, you must use that port instead of the 16pin port inside the car. You will need a 16pin to 20pin BMW adapter. These can be purchased on amazon for 5usd or so.