HID Headlight FAQ and Installation

The following writeup attempts to answer some of the common questions about high intensity discharge (HID) automotive headlights.  There's also a DIY description and photos of installing a conversion kit into the 2003 and up Hyundai Tiburon.

HID Frequently Asked Questions (FAQ)
1.  What are HID's?
2.  Why install HID's?
3.  What is meant by color temperature?
4.  What are some good quality brands to look for?
5.  What is included with an HID conversion kit?
6.  How does this stuff work together?
7.  Should I replsce both my high and low beams with HID's?
8.  Wow, HID kits are expensive.  Can't I get the same look and light output from the "HID-look" bulbs?
9.  Are HID's legal?

Installation - 2003/2004 Hyundai Tiburon

1.  What are HID's?
The best way to describe an HID headlight is to compare it to a more conventional halogen headlight.  A halogen bulb consists of a wire filament surrounded by an inert gas.  When electrical current is applied to the filament, it glows brightly to produce light.  Contrast that with an HID bulb which has no filament, but instead consists of xenon gas, mercury, and metal halide salts.  The xenon gas is ignited by an arc of high-voltage current and glows brightly.  Also, the high voltage is supplied by a ballast, so in these respects it is like a fluorescent light.  HID's are original equipment generally found on luxury and exotic cars but are progressively finding their way into the mainstream.  For example, the 2004 Mazda 3s at ~$17k will include HID's.

2.  Why install HID's?
If chosen properly, the improved light output of HID's will give you a better field of vision and thus improved safety.  Plus, let's admit it, they look cool.

3.  What is meant by color temperature?
The Kelvin (K) is the unit of color temperature.  4100K is the brightest, most natural white light similar to that of daytime sunlight, and therefore the HID color temperature used most in the OEM automotive industry.  When you look at the light coming directly out of an HID headlight, it possesses a bit of a blue or purple hue which most people recognize as the expensive, elegant look characteristic of HID's.  For this reason, some HID kit manufacturers produce 5400K, 6500K, 8000K, etc. bulbs that give an even more distinct blue hue but at the expense of overall light output.  For comparison, most halogen headlights have a color temperature around 3200K which gives them a "dingy" yellowish appearance compared to HID's.

Blue light is more fatiguing to the eyes, both to oncoming traffic and to the driver.  Oncoming cars will see your lights for only a brief time, but as the driver, you must deal with it for the duration of your drive.  The bluer the tint cast on the road and surrounding area, the more quickly your eyes become tired.  It's a personal choice and I recognize and respect that some install HID's mostly for the look.  However, very blue headlights might get you the wrong kind of attention from law enforcement.  Personally, I'd like to benefit from my investment in the way of increased visibility and safety.  Be aware that most of the 6500K and higher bulbs are produced by inferior manufacturers to capitalize on the maketability of "the bigger number must be better".  Their 8000K bulbs may not measure 8000K.  Don't be fooled.

4.  What are some good quality brands to look for?
Generally speaking, Philips or Osram (division of Sylvania) kits are recommended because they are the brands used by the major automotive OEM's.  They count on quality components because dependability is critical to auto manufacturers.  Other brands may use bulbs or ballasts of inferior manufacture that are prone to early failure.  Perhaps even more sinister, some kits tout their use of Philips or Osram ballasts while they covertly use cheap bulbs of unknown origin that burn out quickly.  So it is a good idea to check the brands you buy.  They likely won't be branded by Philips or Osram directly, rather they are usually rebranded by another company.  If the seller doesn't specify who makes their components, it is a gamble.  A low price is very tempting (believe me, I'm the same way), so my best advice is to solicit opinions and do your research before buying.

5.  What is included with a HID conversion kit?
A typical HID conversion kit includes:
The bulbs don't really need any more explanation.  The ballasts are small boxes (usually one per bulb) that convert the car's 12VDC into high voltage AC required to illuminate the xenon gas.  Usually built into the ballast is the igniter initially required to start the bulb.  The wiring harnesses allow you to plug directly into your exiting car wiring with a minimum of splicing wires.  Relays are sometimes included as well, one per ballast.  They use the 12V from the original bulbs to switch in a lower resistance path to 12V to power the ballasts.  They aren't always needed.

6.  How does this stuff work together?

Let's look at the diagram from left to right.   When you turn on your headlight switch, it puts 12V across the relay coil which in turn closes the contacts.  The contacts switch in 12V from the battery to turn on the ballast, which in turn ignites and powers the HID bulb.  Pretty simple concept.

7.  Should I replace both my high and low beams with HID's?
Most of us spend the majority of the time driving with our low beams on.  Compared to the high beams, the lows usually leave the most to be desired.  And HID headlight conversion kits aren't cheap.  As of this writing (Jan 2004), quality kits typically cost $350-$500.   For these reasons, most people opt for low-beam conversion kits only.

8.  Wow, HID kits are expensive.  Can't I get the same look and light output from the "HID-look" bulbs?
Yeah, they don't exactly give them away, do they?  You'll get a lot of strong opinions with this question.  From what I've read, those who've taken the inexpensive route seem to prefer Naxos or Sylvania Silverstar bulbs.  They are direct replacements for factory halogens, meaning they operate on direct 12V and therefore do not require a ballast/igniter.  However, many argue that these produce a light that, while better than typical halogens, is not a true white compared to HID's.  They are a lot less expensive, though.  You can find them for around $30 a pair online.

These HID-look bulbs achieve their light output by drawing more power from the vehicle's electrical system.  Some pull as much as 100W while most stock halogens draw around 50W (typical HID's draw 35W).  Also, while I haven't seen any reports of quality problems from the Naxos or Sylvania bulbs, some of the other bulbs have a nasty reputation for burning out quickly.  Logically, it is probably because of the increased heat due to higher power consumption.  Some users have also experienced damage to their light housings as a combination of cold weather and the increased heat from the bulbs (small bulb housings such as those used with some fog lights, in which the heat is concentrated within a small area).

9.  Are HID's legal?
Installing HID's into a vehicle not originally equipped with them from the factory is technically illegal.  Practically speaking, you stand little chance of being cited for them provided you educate yourself on the requirements of HID lighting and take the necessary steps to ensure you have the right equipment and adjustments to keep it safe.  That is, make sure your vehicle's headlight assembly uses an appropriately designed projector lense (as opposed to a reflector), and of course that your headlights are properly aligned after installation.  Many newer vehicles use projector lenses because stock halogen bulbs also benefit from the "light shaping", but having just any old projector lense does not necessarily ensure that the beam pattern will be correct.  It is absolutely essential for HID's to give the light output a sharp cutoff line to prevent blinding oncoming traffic.  As HID's become more popular, aftermarket projector housings are being produced for some vehicles.

The Department of Transportation (DOT) states that improperly-installed HID's are getting a lot of complaints.  Vendors will usually include a disclaimer that they are intended for offroad use only, but it's no secret that people don't follow this rule.  Now, there are a lot of aftermarket automotive parts that qualify as illegal but aren't strictly enforced.  Logically, the safety implications of blinding oncoming drivers are more serious than, say, an exhaust that exceeds the legal noise level.  So the DOT has actively gone after vendors of HID conversion kits, threatening monetary fines if they continue selling them, and consequently there are now fewer places to buy them.

Be responsible.  Do your research.  Nearly every vehicle make and model imaginable has an enthusiast community on the web.  The people there take this kind of stuff seriously and can help you understand the HID requirements for your car.  Some good resources I've found are:
    Whatever happened to the HID ban scare? - from the NASIOC (North American Subaru Imprezza Owners Club) forums
    Updated ban thread - from HIDForum.com
    Daniel Stern Lighting - thoughtful writeup to the NHTSA (National Highway Transportation Safety Administration)

UPDATE 01/29/04:  I received the following email from Richard <last name omitted> of the NHTSA:
SUBJECT:  Why don't you tell the truth about the 'HID ban'
No HID retrofit kit can be legally sold.  It is that simple.

Richard x. xxx xxxxxxxxx
Chief, Visibility and Injury Prevention Division
400 Seventh Street, S.W., Room 5307
National Highway Traffic Safety Administration
Washington, DC  20590
001 202 366 xxxx V
001 202 366 xxxx F

The opinions expressed in this message are my own and not necessarily the
official position of NHTSA on this matter.  Should you need an official
confirmation of an answer or need a legal  opinion that would be used as a
basis by you for making a decision on a business or legal matter, you
should write to:

Chief Counsel
400 Seventh Street, S.W.,  Room 5219
National Highway Traffic Safety Administration
Washington DC  20590
001 202 366 3820 F

You may use postal service, facsimile or email.  Please include your name,
address, and voice and facsimile telephone numbers.

Installation - 2003 Hyundai Tiburon
Installing the HID conversion kit is very easy.  Decent kits are plug and play.  The Xenon Depot kit I purchased was very straightforward to install.  Simply take out the three bolts that hold the headlight assembly and set it aside.  I chose to mount the ballasts under the lights (see photo right) to keep them concealed as well as out of the hot engine bay.  Judging by its cleanliness, this location does not get wet from rain or water spray.  The ballasts and the wiring harnesses are sealed so a little water wouldn't hurt them anyway.

Then find a location to mount the relay.  I mounted them to existing bolts on the engine compartment sidewall, just behind the headlights (see photo).  Run the fused 12V leads to the battery, and affix the ground ring terminals to chassis ground.

Use a hole saw or spade bit (in this case, 1.0" dia) to drill a hole in the center of the round bulb cover to accept the rubber wiring grommet.  The cover I'm referring to is the sealed cap that keeps dust out of the headlight assembly, and gives access to the bulb to replace it.  Fit the grommet in place and install your HID bulbs into the headlight assembly.  At this point, it should just be a matter of plugging the wiring harnesses together and re-mounting your headlight assemblies.  Fire them up and be sure to adjust the beam alignment to give yourself maximum visibility and prevent blinding other drivers.

That's all there is to it!

This section shares the solution to an issue I was having with my HID kit.  The problem was, when I would turn the lights on, my parking brake and ABS lights on the gauge cluster would come on.  Half the time they would turn off after about 5 seconds, the other half of the time they would stay on until I shut off the engine.  I couldn't find anything actually wrong with the car, neither with the HID's nor with the brake system.  Still, it was irritating, so one weekend I set out to fix it.

Being that a few people have had problems with the electrical system (battery, alternator), I figured it was a large instantaneous inrush current causing the car's voltage to sag and upset the ECU.  I had a capacitor left over from the sound system in my last car, so I went ahead and wired it up in the engine compartment.  When I turned on the HID's, the voltage momentarily dropped by about 0.5V.  Not enough sag to cause any problem, but the parking brake and ABS lights still came on, so that wasn't the fix I was looking for.

I checked voltages and ground continuity everywhere; no issues.  Okay, so maybe it's one of the ballasts.  I tried each one individually and found that it was the passenger side causing it.  That's when I noticed something that had eluded me so far.  The ABS module is located next to the spot where I mounted the relay (on the L-bracket used to secure one of the plastic engine cover pieces).  Apparently, when the relay engages, its magnetic coil interferes with the ABS module.  Bizarre, really.  I can't imagine the relay producing a very strong stray magnetic field, but the ABS is apparently very sensitive.  I relocated the relay to the bolt shown, so that it is basically laying down about 6" away from the ABS module, and the problem is gone.

Maybe no one else has run into this, because it would mean a combination of having a Tiburon equipped with ABS and choosing to mount the relay in the exact same location as me.  But just in case you have that kind of extraordinary bad luck, here it is.

Return to Tiburon Page

Written by Jason M. Neal  - Revised Jan 30, 2004
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