OEM xenons levelling behaviour

[LizardOfBodom]

Hi!

Can anyone with OEM xenons confirm their auto-levelling behaviour? From what I know, there were versions with just Xenons and with Active Bending Bi-Xenons (ABL) right? So what I would like to know is:

- when you start the car and turn on the lights, they self-level automatically (up-down and left-right if ABL). Does that happen only once per startup or it will do it any time the load is changed? for example - if 2 people sit in the back, will it self-level again or just after the switchoff?

- does any version have active levelling? So when you brake - lights goes up, when you accelerate - lights go down. Same when travelling on hilly roads etc?
If so - how reactive it is? Is that like instant movement or gradual adjustments that cant catch up with quick manouvres?


Appreciate the info. thanks

[upv5]

All cars with Xenon lights must have auto leveling working all the time, on the V50 with BiXenon there is a sensor on the front and rear suspension so the "Brain" knows the position of the wheels relative to the body and adjusts the lights accordingly, so yes it works during braking and acceleration however the headlights only move as fast as the motors that drive them so don't have time to react to speed bumps etc.
Simple check I've used in past is jack front or rear, put an axle stand under car then use jack to lift the suspension, you will see headlights move in response to the suspension. On UK cars the sensors are only on the drivers side so don't try the check on passenger side as nothing will happen.

John

[LizardOfBodom]

Ah ok, thanks for that. From your sig I suspect its the 2009 FL model you are speaking of? With ABL I would think it has more responsive levelling etc, I still wonder how it was done on 2005-2007 models and what kind of motor was used for levelling.

[Proghound]

Both my C70's have had the OEM Xenons, the current one also has the ABL. Good to know that the level adjustment should be constant. I always thought I could hear the old one making small adjustments at slow speeds, although I couldn't notice any visual difference.

When the lights raise to their initial level at startup it's quite fast, a big change in about a second, the same sort of speed with which the ABL on the current car reacts to steering inputs. Unfortunately though, after that the level adjustment must be very smoothed because on the move it has never reacted fast enough to make any noticeable difference at all. In both cars, I have always seen the light level on the road fluctuate in exact agreement with what the front of the car is doing as you go encounter bumps and gradients etc.

[LizardOfBodom]

Originally Posted by Proghound

... In both cars, I have always seen the light level on the road fluctuate in exact agreement with what the front of the car is doing as you go encounter bumps and gradients etc.

Sorry, so did I understand correctly that it DOESNt look like lights are adapting to road surface level? so going over the railway bridge for example, lights will still shoot "towards sky" and not try to compensate?

[Proghound]

Exactly. On the move, I can't see the levelling making any compensations for what the road is doing. So on the way up the railway bridge, the lights will point skyward; on the way down, they'll point at the bottom, until the gradient flattens out and they point along the road again. Over a more sudden bump, I'll get the light cutoffs bounce up and down in exactly the same time and to exactly the same extent that the front of the car does on the suspension.

From my observations, as I understand it the levelling is only generally attitude-sensitive to the car body relative to its suspension (i.e. the back is on average low on the springs compared to the front). It's not reactive to exactly what that attitude is at any particular point in time, and it also has no concept of the actual horizontal. What it ensures it that, other factors remaining unchanged, the cutoff of the lights will appear at the same height/distance at the same place on the road, whatever the load in the back of the car. Whether that height/distance is too high/too far or not, is not its concern.

[LizardOfBodom]

Thanks Proghound, thats the exact information I was looking for. Looks to me that those cars have just load-level compensation but not any of those quick-reacting road-adaptive systems. So technically speaking - its the automated version of manual levelling that halogen cars have...

[Proghound]

Originally Posted by LizardOfBodom

So technically speaking - its the automated version of manual levelling that halogen cars have...

Absolutely

Now why couldn't I have put it as succinctly as that?

[pjuniper]

Thanks for the info. I have just bought a 2010 V50 with xenons to replace a V50 which didn't have them. I couldn't find the headlamp levelling dial on the dashboard, despite lots of searching. I guess thsi explains it!