FG XR6 Wiring

Just got home in the Wifes car after driving from Rotorua to Feilding. Just over 3 hours. I had the park lights and driving lights on for the first half of the trip and low beam on from about Taihape. The dash lights stayed very dull (instrument cluster) and the centre dash multi display ( cd,clock.air cond settings and the after market sat nav very bright) till just south of Taihape when they changed. The instrument cluster came up brightand multi display and sat nav dimmed. This is the first time I have seen the sat nav affected. Are there any known connection problems or earth wire concerns! It still under warranty but I am asking any Ford techs if they have heard of it. Its the sort of fault that could take some tracing so any ideas appeciated. If you turn all lights off and back on it is ok for a short time.
Thanks .

If the sat nav is hard-wired in it would explain the dimming if the wrong circuit is used

Have a sat nav in a BF XR6 but is plugged into the accessory outlet but unlike the FG does not have auto dash lighting feature
I use IGO sat nav software that has a night-time dimmingfeature

Can't say I've heard of it, or our sparky at work either. Certainly isn't a common thing.

On the older BA-BF there was a common problem with the wiring in the light stalk breaking, but this caused the park lights/head lights to stop working depending on which wire broke.

Yea, fixed a bucket load of light switches but never heard of this fault. Ford does come up with some pretty crazy faults though. One of my fav is the boot popping open randomly. All roads lead to the bcm

There is a light sensor on the dash in the middle, that round bubble thing by the windscreen and it alters the dash lights and the centre multidisplay. In daylight the dash lights are low and multi display will be bright and at night this is the opposite for obvious reasons. At halflight in the evenings or mornings there will be times when there is enough light for it to set to day driving and times when the light will set it to night driving. Hope that makes sense.

Thanks Boss17, but that should surely only affect it if the light switch is set to auto, and its not.