hey all, i have a 98 falcon and am trying to install a alpine head unit and cant work out the constant 12V wire (straight from the battery). the list of wire colours in the tech department aren't the same as my stereo, even with a multi meter i still couldnt figure out which wire it is. can any one help me please?

Backup (constant power) +12v = Dark Green / Yellow
Switched Power +12v = Dark Blue / White

Ground = Black wire with tab.

Your after market stereo won't share the same colors, but will run along the lines of red switched, yellow constant etc.

sorry i didn't really explain very well, the standard wires that are there are different from the colours stated in the sound system info post in the tech documents section, except for the second plug with the rear speakers on it, they are the same.

the colours in this list are not the same as the colours going into the original tape player in my car

Wiring for Low and Mid Series Decks

Main Wiring Plug - 12 Pins

Pin 1 Grey / Dark Green Positive (+) Speaker Line for the Right hand side Front speakers (Drivers Side)

Pin 2 Blue / Light Green Positive (+) Speaker Line for the Left hand side Front speakers (Passenger Side)

Pin 3 Brown Button Backlighting (Park Lamps power)
Pin 4 Dark Green / Yellow Constant Battery Voltage (+ Positive power)
Pin 5 Dark Blue / White Accessories Power (As taken from the Ignition switch)

Pin 6 Light Green Telephone Mute (Factory Telephone System)
Pin 7 Red / Dark Blue Power Antenna Output (Positive Trigger) Used to extend the power antenna

Pin 8 Dark Blue / Red Instrument Cluster LCD Backlight and Dimming Signal (Negative)

Pin 9 < !-space-> < !-space->
Pin 10 < !-space-> < !-space->
Pin 11 Blue / Black Negative (-) Speaker line for the right hand side Front speaker

Pin 12 Grey / Black Negative (-) Speaker line for the Left hand side Front Speaker

Secondary Wiring Plug - 8 Pins (Rear Speakers)

Pin 1 < !-space->
Pin 2 < !-space-> < !-space->
Pin 3 Pink / Dark Green Positive (+) Speaker Output for the Rear Left Hand (Passenger) Side Speaker

Pin 4 Pink / Black Negative (-) Speaker Output for the Rear Left Hand (Passenger) Side Speaker

Pin 5 < !-space-> < !-space->
Pin 6 Dark Blue / Red Positive (+) Speaker Output for the Rear Right Hand (Drivers) Side Speaker

Pin 7 Dark Blue / Black Negative (-) Speaker Output for the Rear Right Hand (Drivers) Side Speaker

Pin 8 < !-space-> < !-space->

Was the deck that you removed the original unit or an aftermarket one?
If it was the original one then providing you haven't blown a fuse the wiring you want will be in the plug make sure that you use a good ground when testing...