hey guys. i posted this in the DIY 'how to' section, but its disapeared, so im going to repost it here for anyone who needs the information in the future.
The Blaupunkt 2620 that is installed in the Holden Vectra supports an AUX input, however it is not enabled out of the factory.
The label attached to the headunit
It seems that there are 3 fork pins in the mini-ISO connector that do not match any pins on the back of the Blaupunkt unit. So we can remove these pins and re-use them for the AUX input.
In this image, 2 of the 3 pins have already been removed. The pins on the right are unused, and the pins on the bottom-left are for the AUX input
1. Remove the Blaupunkt 2620 from the dash.
I found it easiest if you start be removing the climate control panel. A gentle screwdriver into the side will pop it out easily. If you need more room you can now also easily remove the storage compartment too.
Now remove the 4 small screws with an allen key.
You need something to stick into each of the 4 holes. I understand that there are tools you can buy (readily available in the UK) – I just made my own using an old coat hanger. Insert the tools a few centimeters, and while pulling them toward the outside of the car, nudge the stereo from underneath – you may need to do each side at a time.
The coat hanger refashioned to help remove the headunit
2. Remove the double DIN cage
Remove the single star-shaped screw at the back (red arrow). I found this next bit a little tricky – near each of the yellow arrows there is a small clip that needs to be pulled inwards before you can pull the cage out. When the cage does come loose, remove the connectors (1 Mini-ISO and 2 ISO moulded into one module) and antenna from the rear.
The double DIN cage
3. Remove the yellow locking bars from the connectors
4. Remove the mini-ISO pins
Remove the 3 right hand fork pins from the mini-ISO connector. You can use 2 straightened staples to disengage the retaining clips on the pins so that you can pull them out.
2 staples inserted into a pin in order to release the retaining clips
5. Create the AUX cable
Solder a 2-core + screen able to the extracted pins, and the other end to a 3.5mm socket (or plug if you prefer).
6. Insert the pins into the AUX position of the connector
The pins inserted into the mini-ISO connector
7. Mount the 3.5mm socket
Some people mount it in the storage compartment, or in the glove box. I’ve used one of the switch place-holders below the hazard light switch.
Put everything back where it belongs and enter the code.
The completed auxillary plug in my car
To enable AUX as a valid input, hold the MODE button until the screen shows ‘AUX off’. Now press the Tune/Track buttons so that the display shows ‘AUX on’.
And thats it.
stolen from: http://craigbeaton.com/blaupunkt2620aux/