the interface complete (autoleads but not sold or manufactured by them anymore) that supports steering and display costs arround 50€ (about43£) and is plug and play. i nicked and translated the page for you to read
Steering wheel remote control + Opel Display Interface for Kenwood car stereo
This adapter allows your Kenwood radio with steering wheel remote control car of your Opel to use, as well as title to let Senderfrquenz etc. to display on your vehicle display. More operating comfort and safety with a steering wheel remote control. Many vehicles have built-in steering wheel buttons to control essential functions of the car radio. With this adapter, you can use this operator comfort even in connection with a car radio or a multimedia monitor. The steering wheel remote control allows you to control some functions of your car radio via the built-in steering wheel controls. Depending on the particular vehicle model can also switch the audio source in addition to the volume control or operate the station search. Please note that your car radio must be prepared for the connection of a factory steering wheel remote control. Easy installation Plug and Play.
Technical Information
Mini DIN connection. The four-pin Mini DIN connector enables addition to the transmission of the steering wheel control commands and the control of the OPEL displays. The four-pin connection contains three data lines for driving the Opel displays as well as a single-pole connection to the factory-installed steering wheel remote control. Display + steering wheel remote control is thus only with car radio via a Mini DIN connector (4-pin) have compatible
Note: Opel-screen display is at Kenwood radios from Bj. 2010 no longer supported, because the "smaller" Car Receivers models a different connection method is used. REM. CON. connection. Due to lack of display control a single data line is sufficient to control the commands of the factory steering wheel remote control to übertragen.Das pole connection cable is called REM. CON. - Which means "Remote Control" means.
Compatible radio list where both works Opel Display + steering wheel remote control
Kenwood (Series 2009 ) KDC-BT 8044 U, KDC-W 7544 U, KDC-W 7044 U, DPX 503 U, DPX 303
Kenwood (Series 2008 ) KDC-W 9537 U, KDC-W 7541 U, KDC-W 7041 U, KDC-BT 8041 U
Kenwood (Series 2007 ) KDC-W 9537 U, KDC-W 7537 U, KDC-W 808 , DPX - 501 U, DPX 701 U
Kenwood (Series 2006 ) DPX 701 U, DPX 501 U, W KDC- 808 , KDC-W 8534 , KDC-W 7534 U, KDC-W 6534 U
Kenwood (Series 2005 ) KDC-PSW 9531 , KDC-W 8531 , KDC-W 7531 , KDC-W 808 , W KDC- 707 , KDC-W 7031 , KDC-W 6531 , KDC-W 6031
Kenwood (Series 2004 ) KDC-PSW 9527 , KDC-W 8027 , KDC-W 7027 , KDC-M 907 , KDC-W 6527 SE, KDC-W 6527 , KDC-W 657 , KDC-WV 6027 , KDC-W 6027 , KMD- 6527