Posted on

Seal Headlights Like a Pro

Seal Headlights Like a Pro

Get a good quality Butyl sealant such as OCI, or even better Morimoto RetroRubber. I was using OCI until the RetroRubber came out, and it’s a much better product for sealing headlights. OCI works alright, but is made for windshields and doesn’t dry the way RetroRubber does. It stays kind of gummy. When RetroRubber dries, it’s more rubbery and was designed specifically with headlights in mind.

Re-sealing is much easier than removing. You need an oven, heat gun, flat head screwdriver, heat-proof gloves, and lots of clamps.

Some information about condensation. Condensation isn’t necessarily caused by a bad seal. It happens because there is warmer air on the inside of the light than on the outside of the light. If the headlight is just getting a little moisture on the lens you can add vents and cover with 3M Goretex patches.

If you actually see water pooling or large droplets, you might have a leak and need to try again.

Step 1:

Set oven to 240F.

Step 2:

Smooth out the old butyl glue.

Smooth out the old butyl glue if not removing it. I use a heat gun to warm it a little and a flat-head screwdriver to smooth it in the channel.

Step 3:

Stretch it out so you don't overfill the channel

Add a string of new butyl or retrorubber to the channel. Stretch it out so that it’s thin, because too much butyl will prevent the lens from seating deep enough into the channel.

Push the lens in place until it sticks on its own.

Step 3:

Protects the plastic from the metal oven rack

When the oven is heated, put the lights on a baking sheet, grill protector sheet (I use Yoshi’s from Bed, Bath, and Beyond), or damp towel so that no metal in the oven is touching any plastic on the housing. Set a timer (I always set 2) for 10-15 minutes.

Step 4:

Use some thick gloves to get the light out of the oven and push the lens in as far as possible.

Step 5:

Clamp the lens into place.

Start clamping the edges. Add clamps wherever you possibly can. The more the better. Good time to reinstall any screws or clips that help keep the headlight lens in place as well. Wait for it to cool down, and it’s good to go.

Posted on

DIY 12V Power Supply for Testing Headlight Components

If you are going to be testing car electronics and don’t want to have to install them on the car every time you need to test something you are going to need a 12V power source.

A cheap, easy, and flexible way is to use an old ATX desktop power supply. These have multiple +12V outputs that work great for testing headlight components. I can light up highs, lows, and other accessory lighting in a headlight simultaneously.


  • An ATX power supply for a desktop computer
  • A toggle switch
  • Quick connectors, solder and soldering iron, or Suitcase taps
  • Heat shrink or electrical tape
  • Step 1:

    Find a power supply. Being a Computer Engineer, I always have spare computer parts laying around because you never know when you are going to need them, right? So I was able to just pull one from an old tower I had laying around. It’s nothing special, just a 250W ATX power supply.

    Step 2:

    Find out the +12V wires. Should be all the yellows, there should be a label someplace on the casing that says the output values of the different colored wires.

    Step 3:


    Find the wires that run to pin 3 and 4 of the ATX connector. This is the power wire that the power switch for the motherboard uses to turn on the power supply. In the above picture, it’s the green and black wires you see clipped and spliced. We need to attach a toggle switch between these two wires to make it easy to turn on the power supply. You can just splice them together, but then you have to plug in and unplug every time you want to turn on or off.

    Step 4:

    This step is technically optional. I actually didn’t do it until I decided to write this up. Now that I have this convenience, I don’t know why I put it off so long. Adding a toggle switch or button to control the power. You just need a switch or button that stays on or stays off for this. I used an aftermarket fog light relay button. They will have 3 terminals. You will need to ground 2 of them and run the power wire to the wire that was on pin 4 of the ATX connector.

    Step 5:

    Plan your connections and solder/splice them in place. There are adapters for 9006 to just about everything else and since I’m a dealer, I have all those adapters so I soldered up two of my +12V outputs to 9006 pigtails. This won’t work for everything though, sometimes you need more flexibility so I recommend keeping a couple for using with alligator clips. This way you can just clamp on to unusual connectors, swap the power from low to high on a dual filament bulb, or send power to individual headlight housing pins.

    Step 6:

    Clean up. It’s a real pain to move a power supply around with all those wires hanging off it. Chop off all the wires you don’t need. Tape or shrink wrap all your solder joints and exposed wires.

    Posted on

    Kelvin, What Does it Mean?

    Since the widespread adoption of HID systems you will often see bulb color specifications with 3000K, 6000K, all the way through 12000K sometimes.

    Kelvin, for those who aren’t big on Physics and thermodynamics, is a unit of temperature measurement. 

    It’s usually used for really high temperatures, for example things like the sun. The sun is actually about 6000K. We use kelvin units to measure the color of light. Different colors are created at different temperatures.

    The lower the kelvin, the more yellow the color, the higher the kelvin, the bluer the color. 3000K is a very deep yellow, 5000K is white, 6000K on things get bluer and bluer.

    Note that higher kelvin does not mean higher output. In actuality the higher the kelvin, the lower the Lumen output. When you get up into the 8000k on range you start getting about the same or less output as stock halogen bulbs.

    If you want the most output, you want to look in the 4500K-5500K range. This is why all the HID kits I sell are 3000K-6500K and either OEM or Morimoto. I am not in it to sell gimmicky parts that don’t perform; I’m here to get the most performance out of headlight systems as possible.

    Posted on

    How to Open Butyl Sealed Headlights

    How to Open Butyl Sealed Headlights

    Tools Required

    1. Oven
    2. Heat gun
    3. Wide blade scraper
    4. Thick gloves
    5. Damp towel or grill protector sheet

    This procedure works on butyl sealed housings. Permaseal is not covered here.

    Opening headlights isn’t an exact science and you can ask the internet, “How long, and what temperature should I bake them at to open them up?” and you will get 10,000 different answers. There is a pretty common range given though which seems to be between 220 for 10-20 minutes up to 270 for 8 minutes.

    General Procedure

    1. Set oven to 240F.
    2. Remove bulbs and metal parts from housings
    3. When the oven is ready, lay the towel or sheet on the rack and put the housing on top. Be careful nothing is toughing any of the metal in the oven.
    4. Set 2 timers (I always set a backup) for 10 – 20 minutes.
    5. Get the housings out when done, and push the wide blade scraper into the groove between the lens and housing.
    6. Start prying the lens away from the housing. Work your way around. Don’t try to go too fast. Get it separated a bit, then move a few cm’s away and start prying again. Some people use a screwdriver for this part, but when you mix a narrow, sharp blade with heated, soft plastic, the plastic is going to get damaged.
    7. As you get one end pried away, you’ll notice the butyl strings off like cheese on a pizza slice. Once it starts to cool, it will start to harden again, and really holds on. If that happens, I use a heat gun on the lowest setting to melt it. You could also use a razor blade; I have done both, but I prefer the heat gun because the glue just shrinks back to the channel or lens instead of falling in and possibly sticking to the chrome.
    8. Eventually, you will be able to just pull it apart with your hands.


    • If you get the glue on your lens and it’s plastic, use “Goo Gone” not “Goof-Off” to remove it. The UV coating will come right off with Goof-Off if you press too hard. First try to just heat the lens again and rub it off with a finger or thumb. If that doesn’t work, use only a very light brushing of Goo Gone, there is no need to push down at all, the solvent will do all the work for you.
    • Using a screwdriver can break or deform the channel that the lens fits in; I use a wide-blade paint scraper for all my prying, and .
    Posted on

    LED High Beam Bulb Flickers When Fog Lights Turn On

    LED High Beam Flickers When Fog Lights Turn On

    I installed a set of Morimoto XB LED Headlight bulbs on a B5.5 VW Passat. 

    If you have a car that the fog lights shut off when high beams are on, this may happen to you as well, so this is not necessarily a Passat-specific post.

    This car comes with a 4 beam headlight system and also has fog lights. There is low beam projectors in the headlights and a high beam reflector. The fog lights are located in the lower bumper grills.

    After installing the bulbs and testing, I noticed the high beam bulbs would flicker badly if the fog lights were turned on at all. Parking lights + fog lights = high beam flicker, low beams + fog lights = high beam flicker.
    I grabbed a stock bulb and plugged it into one of the high beam sockets and tried again. The flashing went away and everything behaved as it should.

    What this told me is that there was not enough resistance in the high beam circuit. I added a single Morimoto HD Load Resistor and that was enough resistance to stop both headlight bulbs from flickering when the fog lights turn on. However the final installation should have a resistor for each bulb.

    Posted on

    Correctional Splitters

    A lot of newer cars have 4 beam systems that already keep the low beams powered on when you engage the high beams. But there are many older cars or cars that originally came with 2 beam headlights that actually shut down the low beams when the high beams are enabled. This isn’t a big deal in halogen headlights because halogens are instant-on. HID’s require a warm-up period though, so if you turn off your high beams while driving at night, you will be driving blind while waiting for the low beams to get back to full intensity. Some ballasts like Matsushita or Mitsubishi Electric only take a couple seconds, but most aftermarket ballasts take between 7-15 seconds to warm up.

    A correctional splitter is an amazing little wire harness that allows the low beams of a car to stay on with the high beams in a 4 beam system when the car doesn’t allow that functionality.

    When we talk about 4 beam systems vs. 2 beam systems we mean a headlight with separate low and high beam bulbs vs. a headlight with a single bulb that has a low filament or high filament that lights up.

    For example U.S. VW Jettas came with 9007 2 beam headlights. Just one bulb in each housing for the low and high beams. In Europe there was the option of a HID housing that had a dedicated low-beam projector and a high beam halogen reflector. When you install the European lights on a U.S. car, it doesn’t know that the headlight has a dedicated low and high beam, so it will shut down the low beams when you turn on the high beams.

    Posted on

    Disabling DRL at Switch on 99-05 VW Jetta

    Disabling DRL at Switch on 99-05 VW Jetta

    MK4 Jettas leave the factory with a bi-halogen (dual-filament) headlight bulb. Since the car has only one main beam, and the the daytime running lights run off those same bulbs, you need to disable the DRLs to install HIDs. The reason being, that the DRL runs the light at 80% power and that will destroy HID ballasts rather quickly.

    There is an easy way to do this that simply involves bending a pin down in the connector of the headlight switch. The pin will be labeled TFL and will be in different locations depending on whether you have a US-spec or European-spec headlight switch.

    The US-spec switch looks like this:

    The European-spec switch looks like this:

    Step 1: Remove the Headlight Switch

    To remove the headlight switch you push the dial in, and turn it clockwise like you are turning on the lights. Once you can’t push it any further, you pull it out towards you.

    Step 2: Unplug the Headlight Switch

    Put your fingers at opposite sides and wiggle the plug side-to-side until it comes out. There is no trick here, it just comes out by wiggling it free.

    Step 3: Locate the TFL Pin

    On either switch the TFL pin is the 3rd one from the edge; depending on how you flipped it, this can vary. The thing to note, is that the pin is labeled “TFL” no matter which switch you have.


    Step 4: Bend TFL Pin Flat

    Now use a flat screwdriver to just flatten the pin so it looks like the picture in step 3.

    Step 5: Plug it Back In

    Plug the switch back in and verify that it works. If your dash lights didn’t come back on when you plugged it back in, it’s either not plugged back in all the way, or it’s upside-down.

    If your dash lights came back on and all the turn signals and everything appear to work, then with the headlight switch in the off position; lower the parking brake if it’s engaged, and if the headlights don’t come on, you are golden. Now you may go ahead and hook up your HID relay without damaging your ballasts or bulbs.

    Posted on

    Current State of LED Headlight Bulbs

    I keep seeing people hailing the success of LED bulbs in taking over HID, and on paper they can be made to look quite impressive, but in practice is this really true?

    The short answer is no, they are not a viable replacement for HID or even halogen lighting yet.

    I installed a set of Morimoto XB LED bulbs on my 2013 Mazda 5. I sell these for $99/pair, and on paper the 3000 Lumen output looks like they should blow my stock 1200 lumen bulbs out of the water. After I got over the initial “WOW” factor, and spent a couple weeks driving with them, I grew to hate them.

    First problem was that the light doesn’t carry far enough. Sure, they are really bright up close, and definitely can put out the rated Lumens, but only up close. The Morimoto XB35 H11 5500K HID kit I was using before and even the stock halogens see further down the road.

    LED’s require special optics just like halogen and HID does. Toyota is fitting their cars with LED projectors now. Those are the proper way to do a LED conversion. Using a projector specially suited to LED lighting’s focal point. LEDs don’t light up the way halogen or HID does, so how can anybody think just stuffing a LED bulb in a halogen or HID reflector or projector is going to light the road better?

    Second problem is that in rain, they are useless. Can’t tell they are on at all. Not a good bulb trait in the Pacific Northwest.

    Third problem, city driving. It feels like driving through the city with your lights off. Sure they light up the signs, but it’s very difficult to see the sides of the roads and thus, pedestrians that could be waiting at a crosswalk and assuming you see them and will stop.

    I think I’ve said enough about the bad. Now the good. Bright, close up light means these are great fog light bulbs if you have an HID kit and want something that has a similar color.

    There are some good LED systems out there, but they are the OEM ones. I would steer clear of LED lighting for low beam headlights until they get the light output on par with HID systems, or even halogen.

    You can run them as high beams and fog lights, but I do not recommend LED bulbs for low beam headlights yet.

    So the final verdict is that, until the OEM makers start making LED systems standard, the aftermarket will continue selling sub-par LEDs using hype as their selling point. Similar to how the cheaper HID sellers did and gave HID’s a bad rap. I will be happy to do retrofits with LED projectors from OEMs. And as soon as I get my hands on a set, I’ll probably run them myself.

    Posted on

    Fluted Lenses and Retrofits

    I get a lot of requests for projector retrofits into housings with fluted lenses where the owners swear up and down that the fluted lenses won’t affect beam output. There are even people who believe that because their housings are Ecode housings, the beam is somehow immune to the effect of the flutes.

    I’m in this business to improve lighting, not for gimmicks or to take somebody’s money without giving them an actual measurable improvement over their previous lighting system. It’s all about performance for me.

    Putting a projector behind fluted lenses negates the entire point of having the projector in the first place. It’s an additional refracting lens that takes the focused, crisp beam pattern from your projector and just throws it all over the place just like a halogen reflector would because that is what a fluted lens is. It is part of the halogen reflector system in lights which utilize fluted lenses.

    Not everybody understands, or is interested in, the physics so let’s show them with a real world example.

    Here is the beam pattern of a Morimoto Mini H1 6.0 projector behind Hella fluted Ecode glass from a mk3 Jetta or Vento (depending on where you are from).


    Here is what it is supposed to look like.

    Morimoto Mini H1 6.0 Bi-xenon Projectors 5_1.0 Bi-xenon Projectors 5
    See how the step is blurred, and doesn’t match the markings made when the lenses were not in place? Also notice how the hot spot is just kind of a blob? That means a lot of your light you just paid to focus is being thrown all over including into oncoming drivers’ windshields. It’s no longer focused and the retrofit has been a waste of money. The hot spot is also not distributed evenly throughout your horizontal field of view.

    The second photo is how a proper HID setup should look. Crisp, clean, and evenly distributed.

    This is why I don’t perform retrofits on fluted lenses. I’m not trying to waste anybody’s time or money and I am not trying to put products out there that other drivers at risk. Show cars are a different story and the only times I will do a retrofit where a clear lens isn’t available.