For those with the H7 headlights, I've discovered a great upgrade for the WEAK stock headlights. Weak would be a compliment to our stock lighting. I absolutely hated the stock bulbs and lens adjustment so I tried to find a solution and have found one that is not very expensive and is easy to do yourself.

The answer to the lighting issue for those of us without the active headlight option is switching to PIAA extreme white plus bulbs. These are not those cheesy blue tinted headlight bulbs that put out less light than the stockers; rather, they are the closest bulb I've seen to actual HID and are very bright. They look to be twice as bright as the stock bulbs and give off as much light as the HID headlights on my recently sold CL600.

My last two Mercedes had HID bulbs and it escapes me why Mercedes chose to use the H7's instead of HID bulbs in our GL's??? However, the upgrade to the PIAA extreme white plus bulbs is the way to go and is the cure for the weak stock lighting. Get two sets of bulbs, 4 total, so you can swap the high beam bulbs too.

The headlights are easy to adjust. After looking at my owners manual, I discovered that the two headlight adjustment screws are easily reached with a phillips head screwdriver from the top of the headlights and the hood open. Make sure you do the adjustment of a flat road so you don't adjust them too high and blind oncoming motorists. You only need a slight adjustment with the new bulbs to make a huge difference in lighting. I don't know why they were aimed so low from the factory but they do need to be aimed higher. The screws on the inside/middle of the housing are the ones that adjust the height of the lighting pattern. I wouldn't even adjust the ones on the outside edge of the headlights.

Here's the vendor and listing for the bulbs on Ebay. Shipping was very fast and the seller gave me tracking numbers shortly after I payed for the item:
http://cgi.ebay.com/ebaymotors/PIAA-...spagenameZWDVW

 

I have a couple questions you might be able to answer; first, how do we know if we have H7 headlights or not? Second, should we also swap out the fog lamp bulbs (that'd be all three sets the guy has left)? Third, are these 50-state legal? Fourth, how might this affect warranty?

Thanks in advance for any help you could give,

Steve

 

If you don't have the active headlights, you have H7's. It will also say in very small etching on the top edge of the plastic headlight lens coverning viewable with the hood open.

The bulbs are 55 watt so they should be 50 state legal. The manufacturer states they give off 110 watts worth of light but only use the legal 55 watts to get there. Their clams are believable given the light these produce. They should not affect the warranty.

I have found the foglight bulbs to be fine for their purpose. Replacing them with set of the PIAA extreme white plus would complete the look.

 

naturally, the advertising claims are embellished and if properly quantified, it
would be quite easy to see that there is no way for halogen H7 lumens to
equate to HID lumens. in addition, using the measures of 55 vs 110 watts
is a poor and improper method of measuring brightness.

 

I think the manufacturer is comparing them to the lumens a 110 watt halogen bulb would produce. They are very very bright compared to the stock bulbs.

http://www.piaa.com/Bulbs/Bulbs-H7.html

 

Thanks for the tip I am going to order them today. I agree - MB should be ashamed of the stock lighting in the GL.

 

The bulbs along with the slight headlight adjustment made a HUGE difference. With the changes, the car is actually enjoyable to drive at night. Before, at hwy speeds, I had to use the high beams whenever I could to properly see the road.

 

Am I the only one who is a little confused about people complaining that the GL's headlights aren't bright enough?

 

Maybe you have the active headlights because the stock bulbs along with the factory headlight adjustment is less than good. When you are coming out of a car with HID lights, the stock bulbs suck.

 

I have to plead ignorance - what is the "active headlamp" system? I guess its not something I have.

I must say that I only drove my GL on the highway at night for the first time a few nights ago and my first impression at 110 KM/H (70 MPH) was that I was about to outrun the headlights. It seemed that the lights were set too low and that they needed to be adjusted upward.

 

I agree, as I too feel the same thing, and at even lower speeds. I wonder if I should have mine checked out during next visit to dealer and if they can raise them up?

 

If you have xenon lamps (HID) than you have the active system which means the lamps turn a few degrees (don't know precisely maybe GL knows) in the direction of your turn. System comes with (on US models) fog lamps that turn in the direction of your turn indicator if your speed is below 25MPH. If you are outrunning these lamps even at 120KPH, they are probably set a tad low, although I remember in my Porche the limit at low dip was about 75mph. Faster than that at low dip did not seem right anyway. The manual has a very detailed procedure (page 514 on US manual) to set the height and check the beam pattern. The procedure does not speak to vehicle height so I would put the vehicle in it's lowest height postion when you run the procedure. Good Luck! PS H in the manual is the distance from the centerline of the bulb to the ground.

 

ReachWest - you have active (Xenon/HID) lights which come as part of lighting package. Looking at your GL's pic in your signature, I see that your fog light is surrounded by chrome trim which is only for GLs with lighting package.

Regarding me outrunning the lights, I don't think I have ever faced that issue. To me, beam distance and coverage is A OK. It's probably because Xenon coverage ends in a line vs fanning out in a manner similar to regular lamps which could cause the feeling that you are about to outrun the lights.

 

I have been upgrading headlights bulbs ever since they became available (early 90's) so i have a lot of experience on this. Light is measured in color (kelvins) and output(lumens). Now the average halogen filament bulb has a color of about 3000k and about 1000 lumens. HID's are 5000k and up and output is about 3000 lumens.HID's color resembles the color of sunlight, a white clean light while regular halogen have a yellow color. HID's color goes as high as 12000k the higher it goes the more blueish it gets. Now just comparing halogens against HID's you can see how inefficient they are, in both color and output. Now just by upgrading your regular bulb to an aftermarket bulb you can increase to a better color and output. High quality bulbs now can almost match HID's color, but not quite the output, but still a vast improvement over stock.The light is whiter so you see better, instead of the yellowish light that just get washed out .One of the first things i did when i got my GL was to change the fog lights bulbs for they were embarassing yellow(i posted pictures here somewhere). I highly recommend changing the bulbs, is a low investment for better safety. I also recommend better quality bulbs(PIAA,Raybrig etc) over the cheap ones for they don't last.
Now as far as adjusting the headlights, i think you have to be very careful and i think there is a safety issue. What you are doing is aiming the light higher at incoming traffic.People will think your high beams are on.

 

Thanks TM4EXC and OKNISH.

Yes my headlamps do turn in the direction of steering. Sounds like I do have the active system. Having said that - they are in dire need of adjustment, otherwise highway driving at night is too stressful. Shall check out the manual to see about adjusting.

 

I think I'm with you Stumblefoot - I'm going to get the dealer to adjust the headlamps. I just spent a few minutes looking at the directions in the manual re adjusting headlamp aim and I'm a bit concerned about messing it up. As Axchung points out, there is a safety issue if its not done properly.

 

Just for a little peace of mind pending the dealer visit (it is Saturday anyway) go out to your garage and measure the distance from the center line from the hid bulb assembly to the floor. Then at dusk tonight get the 25 ft distance from your garage door, (hopefully it is still level) and check to see the height of the triangle image (the little triangle poking up above the level line of the clipped light beam) on the right side of the thrown beam. If the triangle is not poking above the bulb level height at least an inch than they are definitely too low. Good luck and I also recommend leaving the adjustment to the dealer. Finding a true level spot is difficult and the beam aiming does need to be relatively precise.

 

The adjustment should be done on a very dark straight road. Make sure you are in an out of the way area like a dead end so you don't get hit. The projector beams make it easier to adjust since you can see the cut-off line. The manual suggest that you adjust both screws on each headlight together.

Also, you can get another car to line up about 50 ft away your GL but facing it so you can see where the light will hit the other car. Mine is adjusted so it does not shine in the eyes of oncoming traffic or through the back windows of cars in fromt of mine. Raising the headlights slightly and using the PIAA bulbs make a huge improvement.

 

Are the bulbs easy to replace?
John

 

Do you absolutely have to adjust them up or are they ok as is with the factory setting?
John

 

The bulbs are very easy to replace. Get four of the bulbs so you can replace the high beams and low beams. They are worth the price.

I thought the stock setting was unusually low but you don't have to adjust. However, if you raise them a little, you will be very very happy with the results.

 

Thanks, any instructions on repacement steps?
John

 

Step 1: Buy bulbs. Get two sets so you can replace high and low beams.

Step 2: open hood

Step 3: take round covers off the back of headlights. RIghty tightly lefty loosey.

Step 4: take bulbs out of socket. Twist counter clockwise to remove. You have to use a little bit of force to remove them but do it with your fingers so you don't damage the socket. The bulbs unplug from the socket like you are plugging in a lamp to an outlet in your home. Make sure you seperate the bulb from the plug housing. It's tight and is sandwiched against the metal plate of the socket.

Step 5: remove new bulbs from package. do not touch bulbs with bare hands. A clean set of latex gloves is recommended. I used two sets of gloves. One for each headlight housing so I would not get any oil residue on new bulbs.

Step 6: install round covers on the back of headlight housing.

Step 7: turn on lights to make sure they are working. check high and low beams.

Step 8: see if you want to raise the height or if the adjustment is OK. If youwant them raised, proceed to step 9.

Step 9: get a 6" or 8" approx phillips head screw driver, medium head, and go to a dark road or long, straight, and flat driveway. There are two adjustment points on the top of your headlights. You will see two holes in the crossmember above the lights. Under those holes are adjustment screws for the lights. The one in the middle will raise or lower the lights. Slight adjustment goes a long way.

Make sure the lights are adjusted properly and are not too high or too low. At first, you will think they are set too high because you will be able to see that much better and the new bulbs will illuminate objects on the passenger side of the road much much better than the stock bulbs.

Step 10: enjoy being able to see at night with your new bulbs.

 

Again, I would check the beam height by following the procedure in the manual against your garage door, as discussed ealier on this forum. The PIAA H-7 replacment bulbs are very bright and white so if you have them a little high you will constantly be getting a high beam flash from the oncoming cars. Do it to a CHP in this state and you will get pulled over and then the OEM light issue question starts. You don't want that!

 

Thanks for all the information and instructions.
John