head unit nightmare!!

[m40mfa]

hi all,,,i have a 03 plate a4 cabriolet and have changed the head unit to a sony xplod bluetooth unit but for some reason cannot find a switch live and the bluetooth is not working properly i have searched high and low for the correct leads to plug and play does anyone have any suggestions or had the same prob????

[Woorlord]

hi all,,,i have a 03 plate a4 cabriolet and have changed the head unit to a sony xplod bluetooth unit but for some reason cannot find a switch live and the bluetooth is not working properly i have searched high and low for the correct leads to plug and play does anyone have any suggestions or had the same prob????

Ideally, you will need to run a switched ignition live from the fuse box.
Audi's of this age rely on CAN-BUS signals to switch on their head units - hence the continuous live +12v currently at the head unit.

I found a spare fuse slot and introduced a switch live from an adjacent feed for other accessories, like my Snopeer and originally my TomTom, which I had hardwired.

See pictures of my fusebox - Note the red 4A fuse amongst the larger ones!
I used a "blue" flat male spade connector to tap off the ignition +12v rail in the fuse box - I used a couple of wires from an old Nokia car phone kit which had a pre-crimped female spade connector that actually fitted in the fuse box receptacle - you need to pull out the relevant purple retainer strip to fit the new fuse connector.

[Woorlord]

FYI: The Audi "Power" ISO connector has the following connections:
Connector III:
Pin 1 : Bose Signal
Pin 2 : Alarm Ground
Pin 3 : K-Line
Pin 4 : not connected
Pin 5 : not connected
Pin 6 : not connected
Pin 7 : +12v (Constant 12v supply)
Pin 8 : 0v Main Ground

**** NOTE: Be careful not to feed any signals back to the car wiring through Pin 3, "K-Line" since this is a diagnostic connection. Will interfere with VAG-COM and Audi diagnostic systems - check out this link....
http://www.ross-tech.com/vag-com/aftermarket-radio.html

[m40mfa]

thanks so much for your help woorlord sounding lovely now!!!!!!!
really appreciate it xxxx sam :Blush::Blush::Blush::Blush::Blush::Blush::Blush: