Morning, trust you're all good

I've had my 2010/11 (still unsure what version it is!) F2 SD4 HSE for around 18 months now and despite it's high mileage (134k) it's had a loving life and I've been very lucky in this purchase. It's also one of the models with factory HID headlamps which appears to be a bit special (I like to think so anyway!). I love it though, why I didn't buy one sooner I do not know!

Slowly working on fixing all of the nagging items and having a great local garage who specialises in 4x4 vehicles is really helpful for the bigger items but one thing that's annoying me is the relatively dim dashboard illumination. I know it can go brighter as one random day, sitting in the sunshine the dials and LCD screens were glowing like a champ. This was the one and only day though, since ownership they have always been of medium brightness in the day and dimmer than what I would say is simply easy on the eye (at night). The associated dimmer control appears to work over its full travel and has no dead spots or tell-tale issues.

From what I've garnered reading here the auto sensor is the little dome central to the dash up near the windscreen. More recently I also seem to be having the headlights auto switch on in higher than normal ambient light levels - something I feel may be related to this same sensor? I did buy an Autel scanner as recommended on here to see by scanning if there are any error codes related to the problems but alas no smoking gun was to be found.

Could anyone possibly point me towards things I can check or reset or otherwise test to see if I can resolve this matter? I'm of sound electronics mind and have test equipment to hand for any potential deeper investigations.

Thanks, as always in advance for any expert help that can be offered

There are 2 'light' sensors on the FL2.

The dome monitors the outside light/sunshine and will effect the climate control.

There is a small square sensor on the front of the centre control panel that monitors the internal light and I believe this effects the the panel brightness.

Try covering each one of these to see the effects.

The Auto Light feature is also effected by the Rain/Light Sensor on the Windscreen.
The system is described in the Repair Manual and Wiring Diagrams around page 1921.
https://www.dropbox.com/scl/fi/z13lctkhyk5...e5&e=1


If you have an SD4, then it is a post 2010 facelift model. The SD4 Auto is the best transmission to have.

PS there are also 2 light sensors in the rear view mirror to control brightness of reflection.
Be aware that other things effect the light level outputs including velocity, direction, and other factors (weather) FL2 XS SD4 Auto 2010 2012-2017 (21k - 91k miles) (MY2011)
FL2 Metropolis SD4 Auto 2014 2017- (16k - 84k+ miles) (MY2015)
Metro in its 11th Year of (Extended) LR Warranty / Full LR Service History
(Expensive, but Trouble/Worry free - hopefully?)

Last edited by IanMetro on 16th Sep 2025 3:32 pm. Edited 1 time in total

Ian Sir, you are a star!

Thankyou for the detailed information and manual references, appreciated. I have some time later so I'll bury my nose into the manual for the tech info and go out and start doing some tests and observations.

The headlights issue appeared to start after I had one of those drive through hand car washes a few months ago. As I drove away the headlights remained on for the journey home (in warm sunshine). I had a feeling it may have something to do with the rainfall sensor (film from cleaning fluid over it?) so I gave the patch a good clean. It's behaved better since but still seems to switch on at random times of the day. There are no cracks in the windscreen or apparent leaks either (thinking water ingress causing an issue).

I do indeed have the SD4 auto. Given its age the local garage remarked on how good a condition it was in. History appears to place it in the Fens doing horsebox duties (straw in tucked away places!) and stayed well away from deep/salty water which was good. Just need to get the bumps, dents and scratches man onto it as it's got a touch of neglect I could do with resolving.

The auto headlight algorithm is very complicated, as long as it does switch on and off then I wouldn't worry too much about it. As Ian says it is linked into the rain sensor so the lights come on if it's raining, and may stay on for quite a while after, mine also come on in "low angled sun" situations and I am not sure how it is detecting that.

There is quite a time delay (as there also is with the instrument panel brightness) which makes it difficult to work out what effect the sensors are having.

Yes I've tried a number of cover and watch sessions but as you say it's more than just a basic light sensor and reactionary circuit. One thing that the service manual does go into detail about is how the dashboard illumination dimmer modifies a PWM signal and mentions capacitance as a key factor. I'll be interested to see how that variable resistor is acting in this circuit i.e. is max brightness at high resistance or low. If the former then by adding resistance can I fool it into thinking it needs to be brighter I wonder...