My 2014 XF has an annoying problem that the dealer has not be able to fix. Under Navigation Setup, the Auto selection for Day/Night mode no longer works. It always stays in Day mode even when it is completely dark outside. This feature used to work, but then seemed to degrade by taking longer to switch into Night mode. Now, it never switches into Night mode automatically. The dark maps do appear if I select Night mode manually. I took the car to the dealer where I used to live, and they said they replaced the "light sensor" under warranty. That did not fix it. I then moved and took it to a different dealer, who replaced the "light sensor" again (warranty now expired $$$), but it still does not work. I intend to take it back to the dealer who worked on it last, but I am not sure they understand what is going on, and I wanted to see if anyone has had any similar experience.

Here is some more info that may or may not be related:
- I usually leave the headlight control on the turn signal stalk set to Auto. Setting the headlight control to On (low beams) does not make a difference on whether the Navigation screen will switch to Night mode automatically.
- The stalk headlight control in Auto mode works properly. When the exterior light level drops even a little bit (garage, tunnels, dusk, etc.), the headlights come on right away. I can also trigger the headlights coming on by covering up the light sensor that is visible through the windshield (in front of where the interior rear view mirror mounts to the windshield). However, I cannot get the Navigation Night mode to trigger automatically by covering up that sensor.
- When the Navigation Auto mode worked properly, the dash light dimmer switch also worked properly. Specifically, it would dim the instrument LCD (speedometer, etc.) as well as the console backlights and the door blue lights. Now, the dimmer switch does not dim the instrument LCD, which is always on bright. It does still dim the console backlights and the door blue lights.

Questions:
- I assume that the light sensor I described above is used for the Navigation screen as well as the headlights and the auto windshield wipers? Could there be another light sensor someplace that is used just for the Navigation screen Day/Night mode?
- There appear to be two other light sensors that are used to control the darkening of the rear view mirror. One is behind a plastic lens on the right side of the rear view mirror that faces forward. There is another sensor in the top center of the mirror surface itself that faces rear. They both seem to be working properly because I can get the mirror to darken by covering one of them and allowing a brighter light to shine in the other one when the Auto headlamps are on. Do these sensors do anything other than control the darkening of the rear view mirror?
- What is the plastic blister at the front center of the dashboard used for? This is the translucent dome that has a red LED inside. Is there any light sensor in there?

Any thoughts or help would be appreciated.

 

Still hoping for any insight this community might provide...

It would help just to get answers to these two questions:

- Does the light sensor that is located where the rear view mirror mounts to the windshield control the Day/Night mode for the Navigation system?
- The plastic dome at the front center of the dash contains a red LED, whichI believe gives the status of the security system. Is there any light sensor located under this dome?

Thank you for your consideration.

 

It sounds like something’s wrong with your actually head unit (the screen). I don’t know how easy it is to replace. If it’s easy and the dealership has a spare they could try swapping them to see if it fixes the problem as a troubleshooting attempt.

Pretty strange I never heard of this happening.

 

Which light sensor was replaced, there are multiple. The ones in the mirror can be ignored for this. The security LED does have a light sensor in it, details from service manual. Not seeing anything specific to navigation dimming, but there is a blurb about the center message LCD brightness being controlled by the sunload sensor, so it is plausible that navigation is tied in the same way. This sunload sensor communicates with the instrument cluster directly according to the diagram.

There is also the rain/light sensor stuck to the windshield where the mirror is mounted, but that seems meant for exterior lighting, the automatic headlamps. But anything is possible with this car.

 

Many thanks for the replies. The service manual info really helps, litteredwithfaults. It seems very likely that the sun load sensor is the one that controls the Navigation screen since the message center LCD illumination no longer dims with the thumbwheel as it used to when the Navigation screen Auto mode was working. I will find out which sensor the dealer replaced. Assuming they replaced the correct sensor (twice!), it seems like something else is wrong. I asked whether the new sensor needed to be re-calibrated, but they stated that it did not. I will report back.

 

Are you sure that the Nav night mode is controlled by a sensor. I thought it just makes the switch at dusk and back at dawn based on the fact that it knows where you are, time of year etc.
mine switches fine, but eg in the dark garage in daytime it's still in day mode not night mode
(Mine is a 2010 with the older Nav system so might be different)
So as a starting point is your clock /calendar set correctly?

 

The clock is set correctly. I don't think there is a date setting? Also, assuming the above info on the sun load sensor is correct, a wrong clock setting would not explain why I can no longer dim the message center LCD.

Regarding your check in the garage, was the engine running or were you just in "accessory" mode? The dealer told me that the engine needs to be running for the dimming function to work.

I checked my receipts from the two dealers, and they replaced the "rain sensor" module on both occasions. I think the rain sensor is the one mounted at the rear view mirror attachment point and not the "sun load" sensor described above. Therefore, my current working theory is that they replaced the wrong sensor twice.

With the new info, I am now going to back to my current dealer and see if I get any joy this time.

 

does the sun load sensor replacement require removal of the top portion of the dash? coincidentally i am having similar issues with my car thinking its night all the time. and i have the bubbling leather. maybe i can convince the dealership to take care of it and fix my dash

 

Did you get an IMC update done recently at your dealer? I remember performing an update to an XJ recently and the issue started after the update. Needed to perform another update to with newer software to fix issue.

 

It can be accessed through the center speaker cover. Which is very brittle and nearly guaranteed to shatter. $$$$

 

but even if the speaker cover breaks, they can still only just replace that cover. not touching the leather. hmmmmm

 

Looks like Rummy636 had the right answer to my problem. I took the vehicle back to the dealer armed with the info about the sun load sensor. They replaced both the rain sensor and the sun load sensor again, but that did not fix the problem. Then, they looked through the database of software updates and found one that seemed relevant. They performed the software update, and they say the issue is fixed. I will confirm tonight. They did not charge me anything given the multiple times that repairs have been attempted without getting it resolved.

Thanks very much to all here who helped on this issue.

 

well, you were right...they broke the speaker cover. now i gotta deal with them to fix it

 

Having the same issue with mt 2017 XE Prestige. Will take your advice. Thanks.