Adapter Cable and Switch Box

[croydonchris]

Rather that open up your new ELM327 or VAG interface and start soldering pins or switches which will invalidate your warranty and possibly damage your interface depending on your ability why not buy an OBD extension cable from Ebay and a box and a couple of of DIP switches from Maplins or RS Componants and make a switched extension cable as in the picture. Countries other than the UK will have equivilent shop outlets.
You will need an electronic tester or meter to check which pins go to which wires and a basic understanding of switching and which wires not to switch such as pins 4 and 5 that are ground (-ve) and pin 16 (+12V).
The Ebay adverts refer to this lead an adapter (Chinese translation), but it is actually an extension cable. If you do a search on Ebay for :- 16 Pin OBD Male To Female Adapter Cable you will get some listings returned at around £8-36 (or offer) including postage.
The DIP switches can be mounted on a piece of copper tracked mounting board also available from Maplins at around £1-50 to allow connection from the cable and mounting to the box. The copper tracks can be cut in the appropriate places with a small drill held and twisted using your fingers. The cable can be carefully stripped and cut in the middle and soldered to the board. The appropriate links can then be made on the switches.
I have switched input lines 1 3 7 9 to output line 7 for Fiat but have also switched some other input lines to line 7 out for other makes of vehicle. I have also switched lines 6 and 14 on/off as some times you don't want the ELM327 interface to auto-detect the input but rather to select CAN or K-Line input.
There is an added benefit of having a bit more cable length between your laptop/netbook and the Diagnostic connector and some vehicles OBD Diagnostic connectors do not let you plug the bulky ELM or VAG in easily.
Thanks again to Yani.
Regards ~ Chris
PS Sorry about the quality of the picture but you can see what it is about.