Headlight brighter bulb conversion and how to change bulb on mk3 Passat: 9005 to 9006
VW Passat TDI 9005-9006 headlight bulb conversion or changing your headlight bulb
Your North American spec VW Passat TDI probably has dim headlights. This modification lets you use a brighter bulb.
The issue is that it doesn't use a very bright bulb and the plastic becomes opaque due to sun, oxidation, and road wear. There are two solutions: clearing the lenses and improving the light output. so don' for more details. The bottom of the article also shows a picture of the headlight housing and how to change the headlight bulb.
Dremel tool or file
9005 high beam bulb
headlight polishing materials, see procedure below for more details and link
1000 answered questions: polishing headlights
First see if the headlights and windshield are clean. There's no point in brighter lights when it's dispersed at the headlight and you can't see out the window anyways. Then clear up your old headlight lenses if they're yellowed or opaque. Read the related link above for the DIY article. You might not get 100% perfect results because years of sun exposure has faded the plastic internally, but 90% is acceptable. If it's really bad you should sand away a thin layer of plastic and you will get 97% results by going down to the clearer plastic underneath.
Then you want to improve the light output. Take a new 9005 high beam bulb, which is your existing high beam bulb, and use a dremel to grind the plastic guide in the plug and middle tab down. It will then fit into the 9006 low beam socket. The light bulb is the same dimension and the same wattage as your 9006 low beam light, but it doesn't have the painted tip. It's filament position is also identical so it won't mess up the focus of the headlight housing. As long as your headlights are properly adjusted, the light pattern is pointed down so it won't blind other drivers like a high beam. If you don't clear the headlight lenses, that light will be reflected and create glare. It's essential that the lenses be clear before increasing the light output or else you'll just scatter the light and create glare instead of putting it onto the road. It's also brighter than a e-code/eurolight bulb. Pictured below are the spots where you have to remove plastic.
You can try Halogen Infrared Reflector (HIR) bulbs. I've never tried them but many have reported positive results. The bulb filament position and housing is identical to a regular 9005 or 9006 so there is no problem with the reflector pattern and they draw 55 watts, identical to a normal beam. It's beginning to be OEM equipment on some newer cars but the reason they aren't more widespread is because of patents, higher costs, and limited availability. Unlike colored coatings or other gimmicks that you may read about on the internet, this technology was developed as a cheaper alternative to HID bulbs and is real. Do an internet search for more info on the technology but beware of fake HIR bulbs.
HIR bulbs are direct plug-play and due to the higher lumen rating, do not put a HIR high beam bulb in the passat's low beam spot since it is very bright and I believe that it will produce glare. An HIR 9006 is rated at 1875 lumen, even brighter than a halogen 9005 and an HIR 9005 is rated at 2530 lumes. I wouldn't use an HIR bulb in this car when cheaper bulbs are sufficient, so I suggest trying a 70% increase in your low beam with a standard halogen 9005 instead of a 150% increase with an HIR 9005! Glare creates a safety issue by blinding other drivers and the low beam reflector used on your car or euro headlights does not have enough light control to handle much more than a 70% increase in light without producing glare. And remember that if your headlight lenses aren't clear or clean, it also produces glare. An HIR in a high quality projector headlamp housing (not available for the passat) is more reasonable since projector headlamps have much greater light control and cut-off shields.
Do not use aftermarket HID kits. These bulbs will create lots of glare and if they draw more amps, melt your wiring harness or blow a fuse. Your reflector headlight is not designed to work properly with an HID bulb.
Note: do not touch the light bulb with your hands or when grinding the plastic - wrap it in a fresh, clean paper towel to avoid getting oils or other contaminants on the bulb. If you touch the bulb, use rubbing alcohol or no residue electrical cleaner to clean it.
Here is a picture of one headlight with a low beam (1000 lumen) and one headlight with a high beam (1700 lumen), both in the low beam spot. To give you an idea of how this compares to other bulbs, here are the ratings from brightest to least bright. For comparison, E-code/eurospec passat headlight housings use the H1 bulb. The main advantage of the eurospec headlight housing is a different reflector pattern and glass lenses instead of plastic. I have also listed the HIR bulb ratings (see above for HIR bulb explanation and cautions).
the average HID =3200 lumen (average real "xenon" HID lights, not usable with US or Euro headlight housings)
HIR 9005= 2530 lumen (may be too bright for this headlight housing, for high beams only)
HIR 9006= 1875 lumen (low beams, on the limit for light control with this reflector headlight)
Halogen 9005 = 1700 lumen (high beam bulb that you modified or your stock high beam)
Halogen H1 = 1550 lumen (passat eurospec headlight bulbs)
Halogen 9006 = 1000 lumen (stock low beam bulb)
Here is a picture showing the back of the headlight. The black plastic cover has been removed. The light bulb rotates and then pulls straight out. You can remove the bulb connector before or after removing the bulb. The 9005 should fit perfectly.
All these mods are your own risk.