This merger is already paying off. I found a link to "Mattis Ford Falcon Mods Site" while browsing the forums today, and looky what i found...
Pin 6. - Illumination Dimmer signal
This Wire is used to Dim the Button Illumination for the O/Speed, Set, adn Search Buttons, as well as the side mode indicator.
This line can be connected to any Instrument Illumination Bulb, and typically all these lines are coloured Dark Blue/ Red.
Some suggestions on where to connect this line are either the Illuminated Rear Window Demitstor Button, (Dark Blue/ Red)
This line cannot be connected to the Cigarette Lighter Illumination, as this Illumination DOES NOT DIM, when the Dimmer switch is operated.
So for all the people who have fitted the TC aftermarket and are wondering why the dimmer didnt work - therein lies the answer. Ill be giving it a go over the next few days...