Bi-Xenon HIDs Explained


Bi-Xenon HID What!?  
A complete guide to Dual Filament Halogen Bulbs and Bi-Xenon HID Conversions

When it comes to converting halogen headlights to Xenon HID systems, nothing is more confusing than the Bi-Xenon HID Conversion.  The idea is not difficult to understand, but there is a lack of information available on the net explaining the bulb information in detail.

A Dual Filament bulb is nothing but a halogen bulb with two lighting filaments side by side (see fig 1.1).  When your low beam light is turned on, the light produced by the top filament reflects at a specific angle only illuminating the lower light path.  The high beam filament, because of its alternate position, reflects at a higher angle producing the high beam light path.  This allows the vehicle manufacturer to reduce the cost of making a headlight, by combining both low beam and high beam, traditionally in separate housings, into one with a single bulb (dual filament bulb that is).

In order to convert this type of halogen bulb to HID, you must first understand Dual Filament Halogen Bulbs.  This should be simple considering there are only three types...right?


If your vehicle uses these types of bulbs, this information applies to you.

H4 (Also known as 9003,HB2)
9007 (Also known as 9004)
H13 (Also known as 9008)

Why so many names?
H4, 9007, and H13 are the most up-to-date versions of these bulb types, whereas the other bulb names are their previous generations.  Generational differences include changes in manufacturing standards, different materials used to produce the bulbs, improvements in optics/design, etc.

Each of these bulb types have four potential HID conversion bulb types.  Let's take the H4 bulb type, for example, and explain the four options.

H4-1 (Xenon Single Beam H4)

This is the most simple of HID conversions, and also the most limiting.  This will upgrade only your low beam light to HID, leaving the high beam disabled.  This is also the cheapest and most common replacement HID bulb for an H4 Dual Filament bulb and also the worst one to select.  Not only do you lose high beam, you will likely have high beam warning lights on your dash as there are no wires running to your high beam circuit.

H4 Bulb


H4-2 (Xenon Low Beam, Halogen High Beam)

This bulb should only be used in specific situations once you understand how it works.  This bulb adds a halogen bulb off center of the xenon low beam bulb in order to satisfy the high beam requirement.  High Beam light output of this smaller bulb is severely inadequate and should only be used to satisfy state and local vehicle safety inspections.  This is not a true Bi-Xenon HID system.  

H4 Bulb


H4-3 (Switching High/Low)

This is a true Bi-Xenon HID system.  The -3 variant uses an electromagnet to change the physical position of the HID bulb for the low beam as well as high beam.  This moving bulb adjusts the focal length and adjusts light output to a wide angle for high beam, and a tighter more focused light for low beam.  XenonSupply highly recommends the use of this type of Bi-Xenon bulb wherever possible and is the only Bi-Xenon bulb type sold and guaranteed to work.


H4-4 (Xenon High Xenon Low)

This is the most expensive of HID Bi-Xenon bulb types and has largely been phased out due to its extremely high costs and unpopularity among users.  Two independent HID bulbs are placed side by side to produce the low beam and high beam light.  The problem with this design is that each bulb needs its own independent ballast.  In order to fully convert your low beam and high beam to HID with this type of kit, you need four HID ballasts, and wiring harnesses to ensure proper ignition to the HID system.

XenonSupply has always recommended and supported the -3 Bi-Xenon bulb type and uses an industry leading reconfigurable wiring harness for easy installation as well as troubleshooting with these systems.  Each HID kit or Pair of Bi-Xenon Bulbs sold come with an included reconfigurable wiring harness with quick disconnect connections. The reason for its reconfigurability is because not all vehicles are wired the same and each bulb type has its own wiring schematic.  With a XenonSupply made harness, you will be able to easily troubleshoot HID issues if any.

To check out what Bi-Xenon HID kits XenonSupply has to offer, hit the links below for more info.

H4-3 Bi-Xenon HID Conversion Kits   9007-3 BiXenon HID Conversion Kits   H13-3 Bi-Xenon HID Conversion Kits  

If you purchased an HID kit from somewhere else and now you need a reconfigurable wiring harness for your -3 style HID bulbs, don't panic!  Our harness can be used with other HID kits as long as the connectors are compatible. Check out the link for more details on our selection of Bi-Xenon Wiring Harnesses

H13-3 Bi-Xenon Reconfigurable Wiring Harness
9007-3 Bi-Xenon Reconfigurable Wiring Harness
H4-3 Bi-Xenon Reconfigurable Wiring Harness

As always, if you have questions regarding this article, or need help finding the right HID kit for your vehicle, let us know at, or give us a call toll free at 1-800-840-3240.


XS Team

Tags: Tech Blog

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