I'm going to share this with the community. I can't remember where I read about this fix. It could have been here, could have been another forum. But this is how I did it and it worked like a charm.

Everyone knows there are two sensors in the center front of the dashboard. One has to do with climate (the bigger one, I think), and the other houses the alarm LED and a light sensor. This light sensor controls the auto-headlight feature.

I purchased my XJ8 VDP a month ago. I quickly realized the headlights were on all the time, despite the switch being set to "Auto." So, I began scouring the web for a possible fix. Well, I found one, albeit an odd fix. The person who posted this fix was having the same problem. What he found is that, under the smaller oblong dome, there is a smaller plastic dome that covers the light sensor. The plastic of that dome darkens over time, and blocks light from the sensor, causing the car's computer to think it's always night, thus keeping the lights on all the time. This is also why when you turn off the lights the car will give you a warning on the dash telling you your lights are off, because the car's computer thinks "oh **** he turned his lights off at night.) Here is the fix:

Removed the sensor housing from the dashboard by prying it up with a pry tool. Unplugged both electrical connections. Carefully removed the sensor unit from the housing (the one with the LED, the oblong-shaped dome). Once the sensor is out, remove the smaller plastic dome over the sensor itself (take care because this smaller dome could remain in the bigger dome. Also, it's fragile and could break simply from handling it). Once you have the smaller sensor out, take a very sharp razor or knife and scrape a thin layer of plastic from the top of the plastic dome. Once this is done, put the sensor back together, put it back in the housing, reconnect the electrical connections, and reinstall the sensor housing in the dash.

And now my auto-headlights work as they should. They come on at dusk, and go off in daylight. Scraping a thin layer of plastic off the dome allows enough light to hit the sensor to energize the circuit. But there was another surprise that came with this fix.

My electro-chromatic rearview mirror also was nonfunctional. Bright headlights blinded me at night because the mirror would not darken automatically. Fixing this light sensor also fixed my mirror. It now darkens properly. Apparently, the two are connected in some way.

Anyway, I just wanted to share with the group. Attached is a photograph of the smaller dome that covers the sensor still up inside the dark oblong dome. Next to it you can see the opening for the alarm LED.

 

Nice find

 

When your vehicle is in the service bay, it's ignition is powered on during the computer diagnostics phase. The technician turns your automatic headlights off to prevent them from possibly discharging your battery.

 

When your vehicle is in the service bay, it's ignition is powered on during the computer diagnostics phase. The technician turns your automatic headlights off to prevent them from possibly discharging your battery

Tutuapp 9apps

 

Hi question for you :
did yourcar continue chiming once you removed the keys from the ignation when having problems with your auto lighting.