Does anyone here know how the self levelling Xenons work? It drives me crazy when they level all the time & I can't figure out how it works. Seems to me that any device which measures angle would be effected by acceleration. Am I right?

Guys I'm losing sleep over this (I don't really have a life). Can you help?

 

If I am not mistaken there is a sensor in the rear that's connected to the suspension which 'measures' the compression of the rear springs. You are right, anything which just measures angles would be affected by acceleration/deceleration and inclines. a bootload of stuff and people in the back seat will make the suspension squat, this is averaged out by the system and the lights levelled accordingly.

 

Great, makes perfect sense - maybe they use the sensor for the EBD controls.

Now why didn't I think of that?

Thanks for the goods, now I can get some sleep.

 

Don't go to sleep just yet...

If this compression theory is to be believed, it seems to me they would have to use compression information from each corner. Otherwise, it would make a difference if the fat lady sat in the front or the back, or to the left or the right, as far as leveling is concerned...

My theory is that they use two z-axis (ie, vertical axis) accelerometers, located at the front and rear of the vehicle. The two accelerometer output signals are fed to various electronic control units including the headlamp levelers via a mini-network, so to speak (the network is called CAN).

btw, I have another car which has self-leveling headlamps and there is an ECU for each headlamp.

 

>>Don't go to sleep just yet...
>>
>>If this compression theory is to be believed, it seems to me they would have to use compression information from each corner. Otherwise, it would make a difference if the fat lady sat in the front or the back, or to the left or the right, as far as leveling is concerned...
>>
>>My theory is that they use two z-axis (ie, vertical axis) accelerometers, located at the front and rear of the vehicle. The two accelerometer output signals are fed to various electronic control units including the headlamp levelers via a mini-network, so to speak (the network is called CAN).
>>
>>btw, I have another car which has self-leveling headlamps and there is an ECU for each headlamp.
>>
>>
>>

Uh, you lost me at "Don't go to sleep just yet..."

 

I don't know if I'm crazy or what but...

I thought I read a MINI brouche before I bought the car that said the regular headlights also self leveled. I have them (impressed by their brightness for being regular headlights--very white) and don't notice this. Anyone care to comment on that info?

 

ok, the stock headlights (non Xenon) are not auto-leveling, just so ya know

I don't think the Xenon's auto-leveling is dual channel aka independent for each headlight. I've always seen them adjust identically in parallel according to pitch, never independently and/or according to yaw.

[to my knowledge] There are only two sensors, one in the front right, and one in the rear left. This way they can measure both pitch and yaw with only two sensors, albiet with limited accuracy (only a two-axis modeling versus an infinite axis model if they had a sensor at each corner)

(does this make sense, or is it past my bedtime?)
Ryan

 

I remember some people who were installing adjustable lateral links in their cars complaining that the new arms had no provision for a sensor arm that was back there. It was said that it was a sensor for the xenon system, which made sense somewhat. True, if there is only one it would not detect a lopsided car because of a huge person or big cargo (am I being redundant?) on one side, but the tying together of each side by the sway bar would minimize excessive listing to an extent.

I don't have xenons, I never bothered to see if there was a sensor or provision for one back there (yet).

Maybe it's way too late for me as well.

 

OK, last week we installed M7 springs on my car. Now the passenger side headlight won't self level. I was thinking it was just a coincidence until I read this thread, so now I'm worried about taking it into the dealer in case they say my new springs caused it. Has anyone else had this happen after putting on springs? If so, was there a simple fix? Where are these sensors and can they actually be affected by changing the springs?

 

I dont know exactly where they are, but there are two sensors. One front, one rear. I was trying to figure out how to retrofit a complete xenon kit...including auto-levelling, and it called for two sensors. I dont know where they are located exactly, but i imagine that if they were located on anything concerning the springs, we would have heard about them by now in one of the spring install threads.

The sensors are then sent to a ZKE module which is behind your glovebox. This is the brains of the operation. This is then wired to the headlights where the actual levelling occurs.

 

According to the Bentley manual (which has pics too) ...
there is a vehicle level sensor on the "left control arm" of the front suspension.
For the rear it also says "level sensor ... left control arm" but this would disagree with what others have said in this thread.


In any case, working on the springs seems to require removal of the sensors; maybe they were not correctly refitted or maybe they were damaged. Either way it seems that it is not a coincidence and you may end up paying for a repair.

UPDATE: MINI Complete also mentions the sensors (see attachment):
With automatic headlight levelling, the load status and its changes are recorded by means of two height level sensors (potentiometers) located at the front and rear axles. The information from these sensors is communicated back to the DHL module.

 

Yes, it sounds like whomever installed your suspension kit dirturbed one (or both) of the leveling sensors for your xenons. I just installed a suspension kit on my 05 MCS and it's easy to do the install without having to mess with the sensors. You simply have to strap the left (i.e. driver's side) spring so that you can pop it out. If you don't strap the spring (to keep it somewhat compressed), then you have to pop the lower ball joint on the control arm instead and that requires that you remove the headlamp leveling sensor. The Bentley manual suggests that you mark the sensor's current position before you remove it so that it can be reinstalled back to the same exact place.

If you didn't do the install yourself, then I suggest that you take it back to the place that did it and make them fix the problem for you.

 

Yah thats how i understood it too...one front one rear. Chances are one or both were moved during the install. You could try getting down on the ground and look for them or jack up your car and really inspect it :smile:

 

Hi, I am Mandaboo's hubby. I did the install, the sensors didn't move, but I am thinking that they are out of position due to the 1.3" drop. The angle of the sensors has changed, causing a "freaking out" of the angle. I am thinking of making two shorter arms for the sensors to compensate. Hows that sound to you guys?

 

When i changed my springs on my 04' MCS with Xenon's to H&R's i had no problem with my headlights.........

I think i remember seeing a small box on the rear of the car but it never came close to anything i was working on. I also removed the full strut for swapping the springs, didn't know you could or would want to keep the strut on the car while changing the spring.

 

I am sketical that the xenon self-leveling is this sophisticated. I think the front and back sensors are just potentiometers. The compression of the spring pushes on the level which rotates the wiper inside. The relative movement of both sensor indicates the pitch and the servo tilts the xenon headlights to compensate. If both the front and rear sags the same amount then the net difference is zero - no pitch change.

Though I can be wrong as I haven't examine them nore inspect the head lights closely.

 

Does this mean that during a hard take off, you turn on your headlights taht they will be aim themselves to low? Or vce-versa for a hard brake and on?

 

Perhaps ... but you will notice sometimes that the headlights will re-level themselves "if they feel the need"; so there is a continuous monitoring & correction process - presumably averaging the angles over an extended drive period.

 

I'm still going back to the post about just ONE headlight not leveling after the suspension mods. Wouldn't the sensors send the signals to BOTH light modules? I can't see them working independently.

The reason I'm asking is that one of the xenons on my '04 MCS (passenger side as well) doesn't level. It lights up the road about 2' in front of the car. I called the dealer, they told me to bring it in and they'll probably replace the light assembly. The thing that worries me is that I remember reading a post where someone had issues that were related to the ECU, not the light assembly.

I love the xenons, but I can't help but think that sometimes simpler is better.

 

I just looked up the Bentley service manual. It does not go into much depth but it states that there is a headlight leveling module (LWR). It monitors the angle of the car via two hall effect sensors. This then automatically adjust the vertical position of the headlights (means they both gets the same adjustment) thru two stepper motors in the headlights.

If your passenger side does not level (move a bit) when the driver side doing the leveling sequence it is likely a bad/stuck stepper motor inside the headlight. You should check the connector to the headlight also. The LWR is located behind the glove box to the right.

 

I did not even notice before that it was only one side not auto-levelling!

I would tend to agree that the sensors are shared by both sides.

The engine computer does not get involved with the headlights, but the BC1 does.

 

CAN Bus, I Bus, Omni Bus, Motor Bus, City Bus, Greyhound Bus. . .

I STILL think simpler is better!

Give me a **** and let me level the dang lights myself.

But thanks; the engine bay was pretty dirty when we first looked at the car (it was on consignment at our local MINI dealer) and I had the dealer clean and degrease the engine compartment prior to delivery. They did a real good job - maybe TOO good - I'll pull the connectors and check for corrosion and good contact.

 

I too took out the entire strut assembly. However, in order to get the driver's side strut assembly out of the car (without having to undo any of the ball joints), I had to strap the spring so that it stayed compressed (and hence is shorter in length). This allowed enough room for the strut to easily slip out of the carrier. Once the strut was out of the car, I then unstrapped the spring, compressed it properly, and removed it from the strut.

Basically, if you do it this way, all you have to undo is the three 13mm bolts at the top of the strut assembly (in the engine compartment), and the one 16mm bold holding the bottom part of the strut in the carrier. That's it! It's very easy to take out the struts on a MINI...

BTW, the passenger's side has much more room (i.e. the control arm drops down further than the driver's side does) and so there's no need to strap it. Also, I'm not sure if the strapping is required on earlier MINIs or not, mine is an 05 and there was no easy way to remove the driver's side strut without strapping it first. For the strap, I simply used a truck tie-down, but I've heard of others using large ZIP ties instead.

 

Strange, I've gone through the process twice on my 04' (install then remove) and never had a problem. But i think i see what your talking about, worth a try to make it easier to remove i guess.

 

While on the subject... I have been toying with the idea af putting the 2 or 3 mil black sign vinyl on the crome trim on my CR/B S xenon lights. Is there any way to activate the "squirters" and have them stay in the extended position??? It would make it a lot easier applying the vinyl tape in that area.

Any help???