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Headlights

23K views 130 replies 33 participants last post by  S8NNG8 
#1 ·
Headlights

I've been seeing a lot of posts asking about headlights lately, and a lot of people making bad choices without even knowing what they're doing wrong. There is a lot of really good information out there, but most people don't have the time, skill, or discipline to research for themselves. The following is my attempt to gather information on the topic together into one place in the hopes that people will find this post and be able to answer their own questions. If that doesn't work, at least I'll have something of my own to quote instead of having to write a new response for everyone every time someone has a headlight question.

Put Them on Relays

When talking about headlights for the XJ, the first thing to discuss is their wiring because no matter what your question/concern is, if your headlights are still being powered by the factory wiring, you should change that. In the factory configuration, power for your headlights travels from the battery, through the power distribusion center (PDC) in the engine bay, to the switch in your dash, and then back up to the headlights. This is a problem for two reasons:
  • All of the power your lights will use has to pass through your headlight switch. This often leads to damage/melting of the headlight switch and sometimes can even start a fire especially if you're using bulbs that are a higher wattage than stock.
  • Voltage drop. As energy passes through wire and switches, voltage is lost. What begins as 12 volts at your battery becomes significantly less by the time it reaches your headlights. Small gauge wire exacerbates the problem of voltage drop, and the factory headlight wiring is quite small. A 10% drop in voltage (a little more than 1 volt) reduces headlight output to 2/3 of its maximum potential!
You remedy this with a relay harness. A relay is essentially a switch that is operated electrically instead of physically. A relay harness allows you to power your headlights directly from your battery and with much thicker wire at the same time rendering voltage drop and potential damage to your headlight switch a thing of the past. Putco's H4 relay harness is quite popular and can be found for less than $30. Its quality isn't top-notch, but it does the job. I use one myself. Many other options exist such as Painless, ARB, Daniel Stern, etc. You can even make your own (instructions found HERE). No modification to your XJ is necessary. The harness attaches to your battery or PDC for power, plugs into your stock headlight plugs, and plugs into your headlights. No cutting. No splicing. You will see a dramatic improvement in lighting even with your stock headlights with nothing more than a relay harness, and even if you want to upgrade your headlights, the relay harness is mandatory if you want to actually see any improvement, so DO IT FIRST.​

Aim Them Properly

The next most important thing is aim. Improperly aimed headlights waste light and can endanger oncoming traffic. So many drivers never aim their headlights. They assume that they're aimed correctly from the factory and that aim never changes or needs to be adjusted. Or maybe they assume that their mechanic checks and adjusts aim for them. Or maybe they just never think about it at all. Aim does need to be checked and readjusted periodically, and, no, your mechanic does NOT do this for you unless specifically asked. If you get new headlights, you should check and readjust your aim. If alter your suspension in any way, you should check your aim (because your entire XJ may not be "aimed" the same as before). If you're going on a long trip with a lot of cargo and/or a trailer, readjust your aim because that weight might be enough to tilt your headlights too high. Heck, pothole hits, fender-benders, or a particularly rough day of wheeling can throw your aim off. Aiming your headlights is extremely easy to do. Printable instructions that work for any vehicle can be found HERE

DOT and ECE

Even with a relay harness, many people will still want better lighting as the stock sealed-beam headlights are still disappointing in a number of ways. First, I'd like to discuss the two prevailing lighting standards in the world because they are quite different from each other, and which you are comfortable choosing will determine which products you'll be able to choose from for upgrades.

First, there is the American SAE/DOT standard. This standard is technically mandatory in the US and allowed in Canada and Mexico. Second, there is the European ECE (aka E-code) standard. This standard is required or at least allowed in every other country in the world. The biggest difference between the two is how they control low-beam glare and how much of a priority that control is.
Disclaimer: I have an extremely low opinion of American DOT regulations for reasons I won't necessarily clutter this post with, and while I will attempt to remain objective, I feel I must make everyone aware of this since no one can ever opterate without bias, and anyone who claims otherwise is lying to your and/or themselves.​
DOT allows more glare than ECE and also allows much more gradual transitions from bright to dark throughout its pattern. The top of the low-beam pattern in DOT lights is also not standardised: sometimes it has no sharp cutoff; sometimes it has a sharp cutoff on one side or the other; sometimes it has a flat cutoff clear across the top of the pattern. ECE is more stict about its cutoffs, especially at the top of the low-beam. ECE's pattern allows the light to "kick-up" on one side of the pattern in order to illuminate more of the side of the road and to illuminate signs. This "kink" in the cutoff makes it very important that you select the correct product because most ECE headlights have two versions: one for RHD countries and one for LHD countries. The "kink" in the cutoff also allows precise left/right aiming of the beam--something that the American DOT is hesitant to admit is even possible; DOT headlights can only be aimed left/right with the use of special machinery. Most auto shops do not even own this machinery anymore. Both standards leave enough room for bad products to exist and still comply. Just because something is DOT or ECE approved does not mean it isn't a bad product.

When it comes to the product advice that I give at the end of this post, all recommendations are for ECE versions where applicable because it is my contention that ECE is the superior lighting standard.

Optics and Light Characteristics

Next, let's cover some of the basic properties of headlights. Some of these are pretty technical and of limited practical importance for XJ headlights, so I'll try to keep it short and sweet. You can always do some deeper research on your own or ask me questions if this stuff interests you.

The optics of our headlights are usually one of the following three:
  • Reflection. Light from the bulb is reflected and focused off of the back of the housing. Rampage housings are a decent example of this method being used. http://www.quadratec.com/Assets/Images/67238/67238-lg.jpg
  • Projection. Light from the bulb is focused through a lens. There are projectors for halogen, HID, and LED lights. For XJ's, projectors are most common in HID retrofits, and in one of our two top LED headlight choices. Most times a "projector" occurs in a halogen housing for an XJ, it is a crappy gimmick of low quality and not a true projection headlight. With the perfection achieved by many reflected and fluted halogen housings, my advice is to simply avoid halogen projectors for the XJ unless you know exactly what you're doing.
  • Fresnel lens/fluting. This method is very common for halogen housings and utilyzed by most of the best. Fluting allows very precise control over where light goes by dividing the lens into many different angular sections/prisms. An example of this method can be seen in this Cibie housing http://dsl.torque.net/images/200HRC.jpg
Three characteristics of the light our headlights actually emit are:
  • Spectral power distribution (SPD). Bascially, light sources are usually composed of a spectrum of different wavelengths of light, but it's usually not a perfectly even distribution of all the wavelengths. A particular light source may be more intense/powerful in one wavelength and relatively weak in another. Imagine a line graph across the whole spectrum of visible light with peaks and valleys as it goes from violet to red. Here is a simplified example of various SPD's to help you visualize the concept.

  • Correlated color temperature (CCT). Without getting very technical, this is the overall hue of a light source described in kelvin (K). This is a very common characteristic used by HID bulbs for two reasons. HID bulbs can be easily made to emit light in a variety of CCT. The misconception that CCT = brightness has been planted in the minds of many consumers, so the belief is rampant that a higher K bulb is somehow better/brighting than a lower K bulb. This leads to people buying cheap 8000, 9000, or even 12000K HID's that are awful for visibility thinking that they are somehow better. Daylight tends to be around 5000-6000K depending on angle of the sun or weather conditions. When selecting a headlight, anything from 4000-6000K will be quite effective. Higher or lower are not better, can actually create problems, and will likely attract the attention of law enforcement.
  • Color rendering index (CRI). Diffrent light sources are capable of rendering the true colors of objects to diffrent degrees. This ability is described on a scale of 1-100. While it is debatable how important CRI is to headlights as long as colors can be rendered enough that one can still understand traffic signage, I submit that higher CRI is better if you can achieve it because there is less chance of an object or person appearing to be "camoflaged" against their surroundings with a better CRI. Here examples before and after switching from low CRI street/parking lot lighting to higher CRI lights. Notice how the first images are almost completely "yellowscale" kind of like a sepia phtotograph?


    No headlight to my knowledge has such a low CRI as those "before" shots, but hopefully those help you understand what good color rendering can do.

Products

Let's finally talk about the lights people so often jump straight to asking about.

  • Our stock headlights were sealed-beam halogen. The "sealed-beam" part refers to the fact that the bulb and the housing are one piece. These tend to be of poor quality and generate a lot of waste. When it comes time to replace them, I suggest you buy a quality set of H4 halogen housings and H4 halogen bulbs. Halogens are relatively inexpensive both for their housings and for replacement bulbs. They have a continuous SPD that tends to be fairly strong in the longer wavelengths, a very good CRI, and a lower CCT usually around 4000.

    My recommendations for housings include:
    • Autopal
    • Hella
    • IPF
    • Cibie
  • Also common these days are high-intensity discharge (HID) headlights. These are controversial mostly because of the ignorance of consumers leading them to buy poor-quality products and misuse them in ways that are very dangerous for themselves and others on the road. Because an HID bulb uses an arc through a tube of gas much like a flourescent bulb instead of a filament like a halogen, optics for one CANNOT be used for the other.

    Details regarding the difference in HID lighting vs halogen and its benefits/drawbacks can be read HERE. Because Daniel Stern does such a good job, I won't reinvent the wheel and clutter this post.
    A halogen bulb has a cylindrical light source: the glowing filament. The space immediately surrounding the cylinder of light is completely dark, and so the sharpest contrast between bright and dark is along the edges of the cylinder of light. The ends of the filament cylinder fade from bright to dark. An HID bulb, on the other hand, has a crescent-shaped light source -- the arc. It's crescent-shaped because as it passes through the space between the two electrodes, its heat causes it to try to rise. The space immediately surrounding the crescent of light glows in layers...the closer to the crescent of light, the brighter the glow. The ends of the arc crescent are the brightest points, and immediately beyond these points is completely dark, so the sharpest contrast between bright and dark is at the ends of the crescent of light.

    This diagram shows the very different characteristics of the filament vs. the arc:



    When designing the optics (lens and/or reflector) for a lamp, the characteristics of the light source are the driving factor around which everything else must be engineered. If you go and change the light source, you've done the equivalent of putting on somebody else's eyeglasses: You can probably make them fit on your face OK, but you won't see properly.
    HID has a discontinuous SPD, relatively low CRI, and CCT can vary.
  • Becoming more and more popular these days is light-emitting diode (LED) lighting. LED's need less energy than halogen to generate the same amount of light, but more energy than HID. They generate heat, but not much, and the heat is not near nor easily directed to the lens of the headlamp which can make them problematic in very cold/snowy/icy areas--without enough heat on the lens, the headlights can end-up getting covered in snow/ice. They are extremely long-lived--lasting 10-50+ times longer than halogen bulbs and 20+ times longer than HID. They are very durable, and virtually unaffected by physical shocks/jolts unlike more fragile halogen and HID bulbs who can have their lifespans reduced or even ended simply from all the "rough-housing" a Jeep owner may put them through while wheeling.
    They have a discontinuous SPD but can emit white light without having to use a lot of disruptive blue wavelengths to do it. This ability of theirs is actually causing a lot of lighting science to shift and reevaluate how light is described and used.
    I am only aware of two choices worth consideration at this time: Truck Lite and JW Speaker. I feel the JW Speaker is significantly superior, but they much more expensive than the already expensive Truck Lites. JW Speaker also has a model for XJ Wagoneer guys who have a headlight size that can be very difficult to replace with something of high quality.
    Before anyone asks, no, LED "bulbs" that plug into halogen housings are not a good choice.

Recommended forum for more technical discussion/info: candlepowerforums.com/vb/forumdisplay.php?87-Automotive-Motorcycles-Included

Additional reading and photos can be found at:

It has come to my attention that some people question Daniel Stern's credibility and lack the courage to contact him directly, so I asked him. Let me also point-out that I sent my email to him on a Saturday... I received a response from him within two hours. His customer service is spectacular. Please see attachment.
 

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#2 ·
I plan on updating this post in the future with information on bulbs as well as potentially including more photos; I simply ran out of steam after working on it for so long, but figured I could post it now in its "unfinished" state since it does work in its current state. I hope this helps, and feedback is welcome especially if anyone feels I should include more or less technical information in the interests of keeping this informative without being intimidating.
 
#4 ·
With stock XJ headlights being less than optimal, this is good info to have handy so I added this thread to the "Useful Writeups" sticky. :thumbsup:
 
#10 ·
Got to thinking today how great it would be if all of us in the know would convince as many of our friends/family/neighbors to let us simply aim their headlights for them. Takes minutes and needs no materials other than a wall and some sort of writing/marking tool (tape, pencil, chalk, marker, etc).
 
#12 ·
An excerpt of an article already linked withing post #1 was quoted, honestly, because I don't trust people to actually follow links and read when I tell them too, so I provided a short quote of what I feel might be the most immediately useful part. There is much more in the linked article, and I hope it will still be read.

Additional links were added to the "appendix" of post #1.

Also provided information about Daniel Stern for anyone who has ever doubted his expertise since he is my source for a lot of information.
 
#14 ·
2001 Cherokee besides the screw I can turn out or in how else can i move the lights? Anyone have tricks in adjusting xj headlights?

I know seal beam adjusters but I need them aimed down more
There is a screw above the headlight that you turn to move the light up and down. There is a screw on the side (the "outside" side, iirc) that moves the light left and right. These screws are all there is, and they should be all you need. If there is a problem, make sure your housing is secured properly; they are held in place by aluminum retaining rings that are secured with four screws--two above the lamp and two below. Make sure you don't have them installed upside down. In the event you're using ECE headlights, make sure you have the correct type for you county. There are two different types--one for those who drive on the right and another type for countries who drive on the left side of the road.
 
#16 ·
Off hand do you know if turning to the left aims the light down?
It shouldn't. I don't even see how it is possible given the way the whole thing is assembled. One screw controls up/down. The other controls left/right. It really is that simple, and if you can't get them aimed, there is something wrong.

What headlights (housings and bulbs) are you using?
 
#18 ·
Delta housings with hids.
That's your problem. You're using HID's with Halogen optics. Something I say is a no-no multiple times throughout my original post. The reason you can't seem to aim your headlights down enough is because halogen optics often result in a large amount of light being thrown upwards from an HID source among many other problems such as artifacts, hot spots and light being wasted to the sides and downward.

Delta is a fine halogen housing. If you want to make the housings work for you, buy some Phillips, Osram, Narva, or Flösser bulbs. Just regular white ones, not the blue garbage. If you want the HID's to work for you, get some Morimoto projectors from TheRetrofitSource.com and fit them into a cheap set of housings with clear lenses.

Because an HID bulb uses an arc through a tube of gas much like a flourescent bulb instead of a filament like a halogen, optics for one CANNOT be used for the other.
A halogen bulb has a cylindrical light source: the glowing filament. The space immediately surrounding the cylinder of light is completely dark, and so the sharpest contrast between bright and dark is along the edges of the cylinder of light. The ends of the filament cylinder fade from bright to dark. An HID bulb, on the other hand, has a crescent-shaped light source -- the arc. It's crescent-shaped because as it passes through the space between the two electrodes, its heat causes it to try to rise. The space immediately surrounding the crescent of light glows in layers...the closer to the crescent of light, the brighter the glow. The ends of the arc crescent are the brightest points, and immediately beyond these points is completely dark, so the sharpest contrast between bright and dark is at the ends of the crescent of light.

This diagram shows the very different characteristics of the filament vs. the arc:



When designing the optics (lens and/or reflector) for a lamp, the characteristics of the light source are the driving factor around which everything else must be engineered. If you go and change the light source, you've done the equivalent of putting on somebody else's eyeglasses: You can probably make them fit on your face OK, but you won't see properly.
If you want HID, buy a quality product and use quality HID projectors.
 
#19 ·
The delta bulbs were horrible and not bright at all and I basically ended up paying $130 for housings. I did buy a good brand hid bulb and I did not want to try to retro fit projectors into my jeep. All I know is I can see a lot better with what I did now. I understand the write up and how many people don't like hids and all that but they do work great if properly installed. My right one is fine so I'm thinking my bracket to hold housing in is off due to install years ago with the delta lights and I had to bend bracket due to rust and a bolt wouldn't come out years ago.
 
#21 ·
but they do work great if properly installed.
They do work great if properly installed. I have nothing against HID's at all. What I do have a problem with is improper use/installation of HID's. As long as you have them installed in halogen housings, they're NOT properly installed and likely a hazard to other drivers on the road. Sorry.
 
#20 ·
I know a few guys out my way who run hids in headlights and fog lights and never had any problems and been years since they have installed them with just an upgraded headlight. Everyone buys led light bars and those are expensive and the led headlights that are $500 plus. I spent $80 and can see a lot better than stock and was easy to install.
 
#23 ·
That depends on what you're willing to spend.

You can keep the stock housings, restore them with something like http://www.autogeek.net/plastik-lens-cleaning.html, and get a set of nice halogen bulbs.

OR

Kolak used to sell some ECE halogen housings. kolak@aol.com. The pattern on the left is original; the pattern on the right is the Euro.


OR

You can always do an HID projector retrofit using some cheap eBay housings (clear lens, no fluted). http://www.hidplanet.com/forums/showthread.php?50913-1998-Jeep-Grand-Cherokee-(ZJ)-MH1-Retrofit http://www.jeepforum.com/forum/f197...-3-4-ton-37s-745686/index11.html#post12042496


There are a lot of crappy eBay/ricer headlight options out there for the ZJ, but back when I was prepared to buy a ZJ if I found one, these were the three courses of action I had considered.

Regarding fog lights....they are so unimportant that as long as you use something that has a horizontal cutoff and is aimed correctly, I don't care. Most people overestimate and overuse fog lights--they should never be used except in the worst of weather conditions: the kind where you don't feel safe driving more than 20 mph or so. I am partial to JW Speaker for a number of reasons and would probably use JW Speaker Model 6048 fog lamps (not to be confused with their 6048 auxiliary lamps).
 
#25 ·
I would not use stock housings for a projector retrofit because you don't want a Fresnel (fluted) lens in front of the projector; you want a clear lens that won't alter the beam in any way since the projector has already done all of the focusing. That is why I just recommend picking-up a cheap set of housings off of eBay or wherever to use. Plastic or glass lens is your choice, but make sure it is clear (not fluted).

There is some modifying/fabrication necessary to do an HID retrofit. I posted links to two different write-ups as well as gave you the name of TheRetrofitSource.com as the place to buy projectors (I like Morimoto's projectors, but I'm not quite as much of an expert in all the HID options out there as I am in halogen or LED).
 
#27 ·
Led headlights the way to go?
There are none for the ZJ that I'm aware of.

The only ones for the XJ worthy of consideration are Truck-lite, GE Nighthawk (Truck-lite clone), and JW Speaker 8900.

There are lots of LED bulbs made to just plug-in where an H4 halogen bulb would go, but I do NOT approve of their use at this time for the same reason that plugging an HID bulbs into halogen optics is a bad idea.

As the original post (that I'm beginning to doubt you read) details: halogen, HID, and LED all have their pros and cons and all have very high quality choices to rival one another, so it is entirely up to you and your personal needs/preferences as to whether or not LED is the way to go.
 
#29 ·
I just have had hids in my bike for years now and I never had any problems with it and brighter than stock.
I never said they're not brighter than stock, and I have no doubt that they are. What I'm saying is that without correct optics, light is being wasted by being cast off in directions that aren't useful and in artifacts/hot spots--you're not getting the most out of them AND you are a hazard to others. While you may not have had a problem with them as the user, try being on the receiving end of and improperly installed HID.

I'm not sure what your needs/desires are specifically, but you shouldn't feel as if halogen is somehow inferior. I have 70/65W Osram's in Cibie housings (cost me somewhere around $200 for bulbs and housings), and they're more effective than most headlights out there including many low to mid quality HID and LED options and worlds better than any half-assed and/or cheap HID/LED hack-job.
 
#30 ·
Where did you get those lights? That is why I asked because I would like to get the correct and more efficient light from them. I saw projectors but didn't know if I was suppose to custom fit them in a new headlight assemble for them to work. I know newer cars come with projector head lights.

$200 for your setup isn't bad and I understand about the hids and is why I have mine aimed down a very good amount and I know it is the correct way to install them.
 
#33 ·
Great info! I've stumbled upon it several times and i just got around to reading all the details. Awesome Write UP!!

FYI the link that is supposed to direct to "home made relay instructions" just forwards to a harness on amazon.

I plan on doing this soon since my headlights are quite dim - one is almost yellow. i noticed backing into my garage the yellow headlight is pointed dead center and about 3 feet too high! oops! (i just got the thing a few months ago....i'll be adjusting the aim tomorrow)

Anyways - i've got other lighting projects i'd like to do in the near future and wondered if anyone had used a relay box and/or a fuse box for extra accessories. If i'm going to install these i might as well use them for the headlights as well, right?

Anyone use these (or similar) for their projects? They both have very good reviews on amazon. With my headlights so dim i need the excuse to go ahead and pull the trigger and buy them, which'll help me get moving on the other projects!
 

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#34 ·
Great info! I've stumbled upon it several times and i just got around to reading all the details. Awesome Write UP!!

FYI the link that is supposed to direct to "home made relay instructions" just forwards to a harness on amazon.

I plan on doing this soon since my headlights are quite dim - one is almost yellow. i noticed backing into my garage the yellow headlight is pointed dead center and about 3 feet too high! oops! (i just got the thing a few months ago....i'll be adjusting the aim tomorrow)

Anyways - i've got other lighting projects i'd like to do in the near future and wondered if anyone had used a relay box and/or a fuse box for extra accessories. If i'm going to install these i might as well use them for the headlights as well, right?

Anyone use these (or similar) for their projects? They both have very good reviews on amazon. With my headlights so dim i need the excuse to go ahead and pull the trigger and buy them, which'll help me get moving on the other projects!
Thanks for letting me know about that link. I fixed it now. It now correctly links to http://jeep-xj.info/HowtoHeadlightLoom.htm

I have basically that same fuse block sitting in my garage waiting for a day I can install it and wire everything to it. There are lots of guys who've done home-made relay boxes as well--some really amazing work. Just search around cuz I don't want to really go off of the topic of headlights here.
 
#36 ·
I am going to retro fit projectors in my headlight so the aiming is better and not in the view of other vehicles. I have noticed that newer cars that have hids installed from factory are still blinding and can hit me in the face while driving unless on a flat road. But I going to end up having this guy make projectors for my Zj and I am going to give it a try on my xj.
 
#38 ·
I have noticed that newer cars that have hids installed from factory are still blinding and can hit me in the face while driving unless on a flat road.
  • Aim isn't permanent, and most car owners don't even know how to change their own oil, so I guarantee they're not checking and resetting their aim.
  • Even perfect aim can get into people's eyes if you crest a hill or go over a bump/hump in the road.
 
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