Low beam = Driving lights used with oncomming traffic
High bearm = Much stronger light but will blind oncommng traffic
(I always mess up the terms used in the UK so hope this helps with my Yankee speak)


Hard to fit this one in the Title. Let me explain. I have a 1998 XK8. This year has a bubble level mounted by each headlight's adjustment knob. The instructions say to park on a level surface then adjust the knob so the bubble is in the center of the level for each headlight. Once it is in the center both headlights adjustments are maximized.

Not too many large perfectly level surfaces around here. Absolutely none certified level . So whereever I park her to adjust these lights, I will need to use some reference plane in/on the car to see how level she is with respect to the road surface.

Q1: Anyone know if one exists?

I used the door sill tonight (where it say's Jaguar XK8 on that silver plate), but I can't help but wonder if it slopes. After all the ride height for front and rear measurements differ right?

Things are better after the adjustments tonight but I want to do everything I can to get as much as I can with this adjustment. I am frustrated with the low beam performance. OTOH I love the high beam performance.

It took me a while to realize that the lights (high & low) are both adjusted with the one knob. There is no obvious way to adjust one and not the other.

Q2:Is there any way at all I can adjust low light without impacting the high light that you know of? Two nights ago I adjusted the low beams by eye for maximum distance. Loved it, they did much better, but as soon as I turned on the high beams I realized they are pointing too far up in the air. Ironically the reflective road signs actually hurt my eyes with this configuration!

Q3: Has anyone else gotten frustrated with this, pulled off the tire and went in to adjust the fog light to compensate for the Low beam's poor performance? As I recall from the one time I changed the fog light bulb, there might just be an adjustment in there for the fog light.

FWIW: Yes I did purchase the $50 "Extra Bright" low beam bulbs. Not much of an improvement.

Thanks for your thoughts.

John

 

John,

You're just setting the headlamp level - not calibrating the vehicle for a mission to Mars.

Note the instructions refer to the surface being level - not the vehicle.

I've always used the door treadplate for the longitudinal level and the passenger floor for the lateral level.

On the subject of US/UK terminology. High Beam/Main Beam and Low Beam/Dip Beam. We use the Dip Switch to go from Main to Dip and vice versa.

Our annual vehicle test for all vehicles over three years old (the MoT so named because it was originally the Ministry of Transport test) includes checking headlamp setting. Presumably the US testing doesn't include this?

Graham

 

In the UK, the headlamps are very different to the US - ours have electrical levelling which is, I think, a legal requirement.
So ............. this may not be accurate but I think once the bubble-level has been correctly set, there's a small nylon 5mm nut which you can turn to set the low (dipped) beam independently from the high (main) beam.





There's another very similar but less accessible nylon nut to adjust left to right.

 

if you have an iphone there is a "spirit level" function in the compass app that is standard in the phone. The long side of the phone is your square edge.

Might help to work out if a surface is level or not...

 

I agree that you're worrying about the wrong level - you need level ground which shouldn't be hard to find.

How the cars sits in relation to the ground is just how it sits - if you set the headlights with the car's attitude modified somehow, as soon as you remove that modification, the lights will be out of level in relation to the road and other drivers.

 

Thanks all.

Graham, you made me laugh, "mission to mars." Its just my nature to try to get as close to perfect precision and accuracy as possible if I can. . .

Guess I'm just frustrated with the low beam's performance. Anything over 30mph on a pitch black road and I'm literally driving ahead of my headlights. That's especially problematic around here, we've got dear ready to jump out anytime anywhere. The fact that no one jumped in and said "yes, me too . . . " tells me this is not a product wide issue and mine is somehow different.

I'll look for those nylon nuts, I appreciate it. When I adjusted the low beams by eye the other day, with the knob that adjusts both lights at once, they were much much better at night. Unfortunately that was what pushed the high beams up way too high. So if I can find the nuts to adjust low beam light vertically, and figure out a way to make the left light's angle equal the right light, that'll be great. I expect the ability to adjust this nut at night with a flash light is non-existant, but I'll figure something out.

We do not have motor vehicle tests for headlights in any US state that I know of. In fact I sometimes wish they did. Driving in a low car like ours makes you really notice any out of alignment headlights comming at you. In my state, New Jersey, they no longer test for any mechanical issues at all. They only look at emissions. You just pull up, they connect a scanner and if there are no trouble coldes you are good to go for 2 more years.

I'll look around harder for a level surface, seems like everything is designed with a slope to elimiate water pooling around here.

There was an interesting news team study I recently saw. There are few, if any, standards for low beam settings in the USA. Without specific standards the tests showed that the auto manufacturers are all over the place. They studied dozens of cars sold here. Almost all of them displayed sub par low beam illumination. Jaguar certainly was not one of the very few that were rated highly.

Thanks again.

John

 

John.


I would be thankful you don't have to comply with United Nations Economic Commission for Europe rule 48 which applies to vehicle lighting. But - if you do, here's how to adjust your lights. Best of luck !!


Dipped-beam inclination

It may be defined as follows:

Either as the angle, expressed in milliradians, between the direction of the beam towards a characteristic point on the horizontal part of the cut-off in the luminous distribution of the headlamp and the horizontal plane,

Or by the tangent of that angle, expressed in percentage inclination, since the angles are small (for these small angles, 1 per cent is equal to 10 mrad).

If the inclination is expressed in percentage inclination, it can be calculated by means of the following formula:

100 x L ) h (h 2 1 

where:

h1 is the height above the ground, in millimetres, of the above-mentioned characteristic point, measured on a vertical screen perpendicular to the vehicle longitudinal median plane, placed at a horizontal distance L.

h2 is the height above the ground, in millimetres, of the centre of reference (which is taken to be the nominal origin of the characteristic point chosen in h1):


L is the distance, in millimetres, from the screen to the centre of reference.

 

When state inspections were the norm the standard for low/dip beams was 2" down, 2" to the right at 25'. Park on flat surface 25' away from a target (garage door, building, etc.) turn on headlights and use a tape measure to determine headlamp height. Take tape measure to target and mark headlamp height. Adjust beams to meet spec. L/R adjustment is fairly obvious when driving and a pain to align a car squarely to a target, especially for a one-time use.

These models have weak low beams but aftermarket HID lamps make a vast improvement. (Please peeps, don't start a "they're illegal..." argument here. If you don't like them, don't use them.) Our cars sit so low that they don't present an issue like a truck or SUV would and with our short, small trunks it's unlikely many of us could add enough weight to make the beams rise noticeably. With the projector type lamps we have they throw a pretty controlled pattern. I have never had an oncoming driver flash me Prices on eBay are very reasonable, around $35 last time I looked. Even if they have a lifetime warranty I suggest buying two sets. If one component goes out you'll have immediate spares available. I've replaced one bulb and one ballast over the past ten years on the cars I have/had. Don't bother replacing the hi beams with HID, they come on too slowly to be of much good unless you're typically driving on abandoned roads where you can leave them on for extended periods. I've made that mistake. Plus I've found that HIDs, in my car, don't throw a distant pencil beam but more like a very wide flood pattern.

 

Manufacturers normally specify dip at between 1% and 2%, which would be between 3 and 4 inches at 25 feet.
Aftermarket HIDs give the impression of improvement, but often put less light into the required area than the correct bulb. The increased scatter makes them seem brighter, but doesn't improve performance of the lights. Physics is physics.

 

If it is 0 degrees angle you're looking for, you can always check for level the way you check a level for accuracy. Place a level on an unknown slope and read. turn the level 180 degrees. If a level is calibrated, it will show the same reading either direction it is placed. 1/2 bubble, 1 bubble or centered.

Park one direction and level the headlights, turn the car 180 degrees and park in the same place and check level again. If the surface was level, the lights will still be level.

If it wasn't level, change the headlight adjustment half the difference. i.e Park one way and zero the level. Turn around. If it's 3 degrees low, bring it up 1.5 degrees. 3 high... bring down 1.5 deg.

After that, if you try it again one direction should show high, the other low, but by the same amount. So... if you are level, it should show 0 degrees both directions. Just like the calibrated level.

I know...it's a lot of messing about, but the surface doesn't have to be very level... just flat and you don't have to measure any point on the car to find level.

Just my

 

Thanks Jay, I wrote this when I was trying to maximize the coverage from the stock headlights. Never got things to a satisfactory performance level until I put xenon lights in a short while ago. Big improvement. Thanks for your follow up, it reminds me to recheck the level on ground that's level, not on the door sill. John