Do Not Sell My Personal Information Jump to content


Recommended Posts

Sorry to appear dim, but I have what some might see as a silly question.

What are 'Discharge headlights' , how do they work, and how do I know if they are fitted to my car.

When reading the manual, it doesn't say much about them and it just says 'where fitted'

Thanks for any help on this.

Link to comment
Share on other sites

High Intensity Discharge headlights or 'HID's' are fitted to your car if you have an SE-L. Sport or F-Sport model. They give off a very white light compared to the yellow light from halogen bulbs fitted to lower models. I am sure someone on here will explain the in's and out's of how HID's work

Link to comment
Share on other sites

High Intensity Discharge headlights or 'HID's' are fitted to your car if you have an SE-L. Sport or F-Sport model. They give off a very white light compared to the yellow light from halogen bulbs fitted to lower models. I am sure someone on here will explain the in's and out's of how HID's work

Thank you for that F.A. I have noticed how white the light is, was on my 220d too. It's the discharge bit that I don't understand. I thin that there is AFS aswell but i don't think that I have that on mine. I think that that is where the lights tend to move a little on bends etc. i don't think that I have that either. Thanks again for your help.

Link to comment
Share on other sites

High Intensity Discharge headlights or 'HID's' are fitted to your car if you have an SE-L. Sport or F-Sport model. They give off a very white light compared to the yellow light from halogen bulbs fitted to lower models. I am sure someone on here will explain the in's and out's of how HID's work

Thank you for that F.A. I have noticed how white the light is, was on my 220d too. It's the discharge bit that I don't understand. I thin that there is AFS aswell but i don't think that I have that on mine. I think that that is where the lights tend to move a little on bends etc. i don't think that I have that either. Thanks again for your help.

Most headlamps work with filaments - thin metal wire that is electrically heated until it is white hot - giving the light. Quartz halogen lamps are filled with gas which prevents the glass from blackening as the bulbs age in a smaller envelope made from quartz glass which can stand higher temperatures. Simplifying, HIDs use a high-voltage from a separate generator (inverter) to break down trace gasses to form a plasma which is what you see - a bit like a controlled spark. They are closer to fluorescent tubes than filament lamps, but do not require the coating that fluorescents have to make the plasma (or discharge) visible. Higher efficiency is achieved and they give a much brighter, whiter light for a lower current from the Battery.
Link to comment
Share on other sites

High Intensity Discharge headlights or 'HID's' are fitted to your car if you have an SE-L. Sport or F-Sport model. They give off a very white light compared to the yellow light from halogen bulbs fitted to lower models. I am sure someone on here will explain the in's and out's of how HID's work

Thank you for that F.A. I have noticed how white the light is, was on my 220d too. It's the discharge bit that I don't understand. I thin that there is AFS aswell but i don't think that I have that on mine. I think that that is where the lights tend to move a little on bends etc. i don't think that I have that either. Thanks again for your help.

Most headlamps work with filaments - thin metal wire that is electrically heated until it is white hot - giving the light. Quartz halogen lamps are filled with gas which prevents the glass from blackening as the bulbs age in a smaller envelope made from quartz glass which can stand higher temperatures. Simplifying, HIDs use a high-voltage from a separate generator (inverter) to break down trace gasses to form a plasma which is what you see - a bit like a controlled spark. They are closer to fluorescent tubes than filament lamps, but do not require the coating that fluorescents have to make the plasma (or discharge) visible. Higher efficiency is achieved and they give a much brighter, whiter light for a lower current from the Battery.

Thank you fjcfarrer, A very a very informed reply which has helped me considerably. I now have a much better understanding. Thanks again.

Link to comment
Share on other sites


@ bluenose

A few facts about the 2nd gen IS headlights:

- If your car has headlight washers then you should have HIDs. This is the easiest way to tell.

- The projector on the car is bi-xenon too. This means that on high beam not only will the separate halogen bulb illuminate, the Xenon projector will produce more light too.

- The car has AFS which activates at speeds excess of 10mph. The projector moves a few degrees left and right with the steering wheel when turning.

- The car has auto-leveling.

- The bulb type for the dipped beams is D4S.

- By default the headlights are aimed pretty low. There is a nut at the rear end of the car that can be used to adjust the height of both headlights simultaneously.

Link to comment
Share on other sites

@ bluenose

A few facts about the 2nd gen IS headlights:

- If your car has headlight washers then you should have HIDs. This is the easiest way to tell.

- The projector on the car is bi-xenon too. This means that on high beam not only will the separate halogen bulb illuminate, the xenon projector will produce more light too.

- The car has AFS which activates at speeds excess of 10mph. The projector moves a few degrees left and right with the steering wheel when turning.

- The car has auto-leveling.

- The bulb type for the dipped beams is D4S.

- By default the headlights are aimed pretty low. There is a nut at the rear end of the car that can be used to adjust the height of both headlights simultaneously.

Hi Exdee, Thank you for this, Yes I do have headlight washers on my car. So you reckon that I do have AFS, I think that the salesman said that I didn't when I asked him. Is there an easy way to tell, or is the movement so minimal as to be barely discernible.
Link to comment
Share on other sites

Go out at night with dipped headlights. If you have you'll notice the light pattern(top edge) moving left and right.

I find it really quite natty....beats illuminating the trees when you go round a tight bend.

Link to comment
Share on other sites

Hi Exdee, Thank you for this, Yes I do have headlight washers on my car. So you reckon that I do have AFS, I think that the salesman said that I didn't when I asked him. Is there an easy way to tell, or is the movement so minimal as to be barely discernible.

Factory xenons will have auto leveling and washers as standard.

AFS is not a Xenon requirement and more of an add on. Hence some MY's will have it and some wont . The easiest way to find out is to use the satellite switch.

dvribk.jpg

Keep pressing right and if you do have AFS you should come across the option to enable or disable it.

Link to comment
Share on other sites

Hi Exdee, Thank you for this, Yes I do have headlight washers on my car. So you reckon that I do have AFS, I think that the salesman said that I didn't when I asked him. Is there an easy way to tell, or is the movement so minimal as to be barely discernible.

Factory xenons will have auto leveling and washers as standard.

AFS is not a Xenon requirement and more of an add on. Hence some MY's will have it and some wont . The easiest way to find out is to use the satellite switch.

dvribk.jpg

Keep pressing right and if you do have AFS you should come across the option to enable or disable it.

Hi again Exdee, went out straightaway as soon as i read your post and YES I do have AFS and it is set to ON. Thanks for your help again. Probably appear dim here but what does MY stand for please?

Link to comment
Share on other sites


If you have an SE-L and you car is a pre MY2011 car (both stated in your info) then you have AFS. AFS was removed from MY2011 & MY2012 cars when they restyled the headlights to include LED DRL's

Link to comment
Share on other sites

It is quite difficult to prove AFS works. It only functions when the car is moving at above 12 mph and is only noticeable on high beam, so cannot be proved with the car stationary unless you can safely jack up both rear wheels to mimic driving above 12 mph. You need a long dark stretch of road with a bend and nothing coming the other way, so that you can drive with it both ON & OFF to see the difference which is slight and only vaguely useful - which may be why it was replaced by DRLs on later models with restyled headlights. If the car has been set to AFS OFF for a long time, the controlling motors may well be stuck and it won't work.

The aim of the HIDs can seem to be set low. This is because they can easily dazzle oncoming traffic because of their much higher brilliance. This low setting is usually the correct setting and raising it may well result in MOT failure and a lot of blinded drivers flashing you.

Link to comment
Share on other sites

It is quite difficult to prove AFS works. It only functions when the car is moving at above 12 mph and is only noticeable on high beam, so cannot be proved with the car stationary unless you can safely jack up both rear wheels to mimic driving above 12 mph. You need a long dark stretch of road with a bend and nothing coming the other way, so that you can drive with it both ON & OFF to see the difference which is slight and only vaguely useful - which may be why it was replaced by DRLs on later models with restyled headlights. If the car has been set to AFS OFF for a long time, the controlling motors may well be stuck and it won't work.

The aim of the HIDs can seem to be set low. This is because they can easily dazzle oncoming traffic because of their much higher brilliance. This low setting is usually the correct setting and raising it may well result in MOT failure and a lot of blinded drivers flashing you.

- I am pretty sure the high beam does not have AFS.

- Lexus have a very poor implementation of AFS. It's easy to prove AFS works on other cars.

- The is250 has the headlights aimed too low in comparison to other cars with oem factory xenons. I personally compared it to an audi b8 and bmw e93. Hence, I've adjusted mine to an extent whereby they still point downwards but overall I think I've managed to raise them by two inches when pointed at 25 feet from the wall. I have never been flashed and no problems at MOT.

Link to comment
Share on other sites

Must admit I don't think I have AFS on high beam.

Definitely do on dipped beam.

Think I also had them move when moving steering wheel whilst stationary on the drive at home.

If I remember I will check tonight

Link to comment
Share on other sites

Must admit I don't think I have AFS on high beam.

Definitely do on dipped beam.

Think I also had them move when moving steering wheel whilst stationary on the drive at home.

If I remember I will check tonight

The swiveling must be pretty obvious for you to notice you have it. Pretty much non-existent on my car. I'll probably have to mount a camera up there to see if it moves or not.

Link to comment
Share on other sites

Wouldn't say it was really obvious but there are two little raised points on the pattern that are quite easy to reference from. They caught my eye the first time I drove at night (bringing the car home from purchase) but I don't tend to be aware that much now. Maybe I have just got accustomed to them moving?

Link to comment
Share on other sites

Nope, I'm talking cobblers! They don't move unless you are driving. Ah we'll, they say the best way to learn is by making mistakes!!

Jamie, go out and check when it's dark. You should see the beam pattern move...I'd describe it " quite noticeable". Maybe yours aren't set to 'on'?

Link to comment
Share on other sites

Lexus describe the AFS system like this:

"At night, a Lexus with i-AFS lets you see around corners. It estimates where you will be in three seconds' time, using sensors that monitor your speed and the angle of your front wheels, and shines the car's headlights in that direction. The left and right headlamps swivel by different amounts depending on the way you are turning; one swivels by 5 deg, and the other by 15 deg.

So when you approach a corner, your lights follow the road ahead rather than simply illuminating the edge of the road. It helps take the strain out of night driving, especially on unfamiliar winding roads."

Intuitively I would have thought it must primarily apply to full beam because dipped beam does not (and should not) give you 3 seconds worth of lit distance unless you are travelling quite slowly. At 60mph 264 ft are travelled in the 3 seconds and pro rata. But apparently it applies to the HID low-beam lights. Either way, it doesn't achieve much - just as with similar systems that have popped up every now and then since the 1950's big Citroen's.

Link to comment
Share on other sites

Nope, I'm talking cobblers! They don't move unless you are driving. Ah we'll, they say the best way to learn is by making mistakes!!

Jamie, go out and check when it's dark. You should see the beam pattern move...I'd describe it " quite noticeable". Maybe yours aren't set to 'on'?

I just can't stand unwanted lights on the dash and 'AFS off' is one of them so it is definitely set to work. It's probably my eyes but there is a good chance that your car being a recent MY has better software and/or hardware for AFS.

But apparently it applies to the HID low-beam lights. Either way, it doesn't achieve much - just as with similar systems that have popped up every now and then since the 1950's big Citroen's.

I think it would be a useful feature if the number of degrees it tilted was better. It will be interesting to see if the new GS has AFS and if it has been improved.

Link to comment
Share on other sites

All I can say Jamie from my own experience is that, driving around pitch black country roads in deepest Dorset, I have found the headlight 'gadget' to be really quite effective. For me it gets the thumbs up.

Link to comment
Share on other sites

We currently have 2 IS250's with HID's, one a 2007 model with AFS and the other a 2011 model with the facelifted headlights incorporating the DRL LED's but without the AFS. I can genuinely say that the AFS feature is noticeable on our 2007 model but I do not miss it on our 2011 model and I have driven 1000's of miles in both cars in the dark on the same roads.

On another note, I think AFS is a better system than the cheaper 'cornering fog lights' found on most newish Mercedes and VAG cars.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share



×
×
  • Create New...