People often recount how the xenon self leveling feature works in a noticeable way. I can't say I have noticed them budge whilst on the road. I did a test. Whilst parked and aimed at a wall, I let the clutch out slowly so that the nose of the car rose upwards. I expected the xenons to level downwards, but nothing happened, the beams just aimed higher up the wall.
I also tried pushing the front of the car down, but nothing happened again.
Has the system got a fault? How can you tell its working correctly?
I suppose you could try using a jack to raise the front? Do they adjust up and down when you switch the car on? I think the pattern is "up - down - level".
When I turn mine on they go up-down-level. I don't think that they move while driving but I have noticed some twitching whiling driving around; may have just been the road. I couldn't imagine that they are supposed to move while driving as they would rarely ever be pointing in the right direction. Does anyone know why they 'self-level'?
More weight in the car, specifically the boot or back seats would cause the backend to be lower therefore causing the aim to be too high. In the US inorder to have Xenon lights it is mandatory to have self levelers to reduce the chance of blinding oncoming traffic.
Mine are always twitching up and down. It's very noticeable, especially when parked behind someone at traffic lights-- they'll level up after around 3 seconds.
When i turn mine on, they light when down, then level up. That's it.
Auto self-leveling on Xenon's is mandatory in UK as well.
I should also add (as posted elsewhere) that I believe my xenon's to be aimed a bit too low. So maybe this is why mine are more active than usual?
Agreed. Upon start-up they automatically level while backing out of the garage (really sooner, almost instantaneously) and you can see it on the back wall, the up and down motion.
So if you do my test it will not show you? Releasing the clutch gradually with the handbrake on causes the bonnet to rise and the boot to dip. The xenons should correct this upward tilt and keep the aim at the same spot on the wall, right?
Not sure about the "mandatory" in the US statement. My wife's CL Type S has xenons and I've never seen them self level like in the Mini. Come to think of it my friend's RX-8 doesn't either. The Mini ones, however, are quite "busy" and noticeable even while driving.
I've also seen statements that headlight washers were also required for xenon's but again, the previous two cars mentioned don't have them. Not looking to start an argument and I am quite open to being corrected.
While driving, the headlights will self-level periodically (every 30 seconds or so?), as well as whenever there's a rapid speed change (quick braking, quick accelerating). I often see mine shift up or down when braking at or leaving a stop light.
You will not see them move if you let the clutch out gradually. They react to sudden speed changes, not gradual ones. If you brake quickly at a stoplight behind another car, you should see the reflection of your lights shift once you stop. (do it carefully though!)
Mine twitch up and down when I'm pulled up behind someone in traffic... To go to the original question of HOW they work, there is some kind of sensor in the slotted area in the headlight unit (where it says Xenon) that 'reads' the patten on the road. I think it gets fooled when sitting in traffic by the highly reflective surface of the car in front's paint or number plate. Don't know if the test described will cause them to level... Try moving a white piece of card or something like that in front of a headlight and see if you can fool it into moving.
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