Install guide

4.2 Connecting the K-line

The K-line is an important connection for the BT telephone module because this is how it

communicates with VAG-COM or other diagnostic software. Without this, the BT module will not be

able to be coded to ensure proper operation in the next section. There is no K-line connection in the

original DB25 phone connector in the trunk. However, there is a simple way to connect this without

having to run new wires into the trunk.

The DB25 phone connector harness includes other wires not listed in the chart in the previous section.

In particular, there are three wires that connected the trunk to the multifunction steering wheel

control unit. These are data wires that the old analog phone system used for communication. These

wires are not needed for the new Bluetooth phone module because it uses CANbus for communication.

This section will describe how to “hijack” one of these dormant data lines to take the K-line

connection into the trunk.

The DB25 phone connector is connected to the front of the car by passing through the left side A-pillar

station. This is the same connector station as shown in section 1.2 to tap into the Reverse Wire signal

for the RNS-E. This location is also conveniently close to the VAG diagnostic connector under the

dash. By making one simple connection, the K-line can be connected to the proper pin at this station.

Remove the driver’s side knee panel (see section 1.1) and left side lower A-pillar trim.