E46 Stereo – quadlock connector

From 2000 and onwards, manufacturers, such as BMW, Citroen, Ford, Mercedes Benz, Peugeot, Volkswagen, Rover, Audi, Seat, Opel and Skoda have sometimes started using a 40 pin connector instead, called the Quadlock. The Quadlock connector consists of a block of 16 flat pins analogous to the two main ISO 10487 connectors. While the physical contact pins are the same, the pin allocation is not entirely the same, and the connector housing is not compatible. In addition to the 16 pins, like ISO 10487, there are minor connectors for optional equipment. They fit within the frame of the main connector, and has coding so that they cannot be interchanged. Minor connector B has 12 pins for audio output signals. Minor connector C has 12 pins for various audio sources such as CD-changers, MP3 players.

Quadlock Cables

Typical wiring diagram for a Quadlock connector

1) right rear + (purple)	5) right rear – (purple/black)	9) I-bus (BMW) / Canbus+ (green)	13) antenna (out) (blue)
2) right front + (grey)	6) right front – (grey/black)	10) phone mute / (Speed Signal) (not required)	14) illumination (orange)
3) left front + (white)	7) left front – (white/black)	11) tel on / Canbus- (not required)	15) 12V battery (yellow)
4) left rear + (green)	8) left rear – (green/black)	12) ground (black)	16) 12V switched (red)

Bose/Karmon Stereo Wiring

The issue i had was a car with a factory fitted Harmon Kardon stereo. You will have the same issue if it is a bose stereo too. The issue is that the stereo was too large to fit in the dash in 2000, so they fitted it in the boot, hence the quadlock connector is in the boot. You can find it by removing the carpet behind the emergency triangle on the left side of the boot. To wire in a new stereo, simply remove the head unit and the unit in the boot, and wire a Quadlock cable up to the front of the car into the dash area. Connect the new stereo cables to that

A back to back short extension cable is available here from TME, which i cut in half and manually extended out to 5 meters in order to make a cheap extension cable – much better than £50 off ebay or amazon. You can then fit the new stereo in the dash board, connect to the extension cable, and wire back into the wiring harness in the boot area.

Door floor plate plastic removal

To remove the plate to wire cables along the bottom of the passenger door, slide the panel backwards to free from the clips. Then, using a strong pair of pliers, carefully squeeze each clip that remains in the metalwork of the car and lift out. Fit back into the plastic trim. Once the wiring is fitted, push the clips back into the body work.