As everyone probably knows, the light sensor on the dash automatically turns headlights and instrument lights on or off, and it brightens or dims certain lights and the nav screen depending on the light level. Recently, when starting the car in the daytime while parked outside, the nav screen goes black after a few seconds. If I start the car at night or inside the garage, the screen comes on and stays on. But, when I back out into the sunlight (or shine a flashlight on the sensor), the screen will go black after a few seconds. The only way to keep it on is to cover the light sensor, but then the headlights come on, the instrument lights dim, etc.
The local Jaguar dealer is stumped and, after TWO MONTHS in the shop, and four hours of labor studying the problem, has said they can't properly troubleshoot the system because I have "non-OEM" equipment installed. Well, yes, I have a radar detector that was installed professionally. I also have some colored LED glow strips in the foot wells and under some upholstered panels on the doors and consoles, also installed professionally.
I'm concerned about running up a huge labor bill (at more than $100 per hour) or paying for components like the sensor, control modules, etc. before isolating the problem. Yesterday, I went to the dealer and told them to give the car back to me, and I refused to pay them for their "troubleshooting" time.
My questions: Would the addition of some low voltage lights (2-3 volts) cause interference with the light-sensing system? Has anyone else experienced a similar issue? Does anyone have any suggestions?
I feel like I'm beating a dead horse.

 

Sounds like you nav module lost it's ability to go full bright and turns itself off instead. Mine flickers a lot which is usually a sign the lamp want's to crap out.

Have you messed with the auto dim feature on the nav settings? Turn it off and see if it makes a difference?

 

Did you try setting the contrast/brightness on the touchscreen? I may be over simplifying, but you never mentioned it...

 

Did you have the problem before you had the additional lighting features added or did the problem start after these mods were made.