I am looking for DIY retrofit tips on swapping Mercedes G450, 2007 Halogen Headlamps to XENON. I bought a pair of used XENON headlamp assemblies and planning to do it myself. I am missing instructions to one of the step that I am hoping to clear it out here. I know that XENON headlights have 4 harness wiring versus Halogen which have 3. As a result, I need to get the 4th harness wire and add it. I don’t know which wire I should be looking for. It will be great if someone can clarify it. Getting part number will be the ideal. Thank you in advance.

Any ideas?

I still cannot get a helpful information. I only know that it is possible but dealer will not do it. Any help is highly appreciated! Thank you in advance!

I don't know the answer, but based upon what you've written I would think that you're going to need to get your hands on a wiring diagram or at the very least get a vehicle with Xenon's side-by-side with yours and trace back the wiring to the fuse box to see what you need. Xenon lights have a much higher power draw than halogens and the relays may be different as well.

When I bought my 2012 GL used, I passed up quite a number of good deals specifically to get the lighting package to avoid what you are doing, because getting info for MB is harder than other makes that I've owned in the past.

Good luck with the project.

Xenons use use less wattage than halogens.

I'm in the same position. I can't believe people would get a vehicle like this without HID lights. In fact, I'm shocked that MB would even offer that.

MB is a business and a shrewd one at that. They know that their customers will pay $2k for the package upgrade that includes the lights. The profit margin on the HID lights is very big so they pad their bottom line by offering substandard product in hopes that their customers upgrade.

I feel MB should build a better product and the HID lights should be part of the base offering. The stock halogens with the stock headlight aiming on my GL was just downright horrendous and unsafe! Upgrading to the HID lights was a necessary due to the amount of driving I do at night.

I think their strategy backfired, considering the number of units that were purchased without it. Either they should have included it or made it less expensive....

MB strategy is a totally different topic. I think their backfiring is related absolutely to everything. Honestly, I am not happy with MB pricing. It just absurd in many ways. For example, replacing speed sensor in the transmission which fails a lot and costs $2400 at stealer. Even more, they won't sell it to you if you will not do it with them saying lots of crap like that only they can do it right. Sorry, I didn't want to insult anyone but I feel MB insults me in many ways.

Anyone ever find out if you could wire this? There are plenty of HID headlamps on eBay for a 2013 but wanted to make sure they fit.

I second that. The stock halogens really don't do a car of this caliber justice. At night I find myself straining to see what I can easily see with my 2003 Camry. We really need to get to the bottom of a retrofit, as I'll definitely buy what I need to buy to make the swap!

I think that what you guys need to do is coerce a guy with the HID's into setting his GL next to one of your GL's and then take a look at what the differences are. The easy part is going to be the light housings themselves. The hard part obviously is going to be the wiring into the fuse box(es?) which you are going to have to harvest from a wreck in a junk yard somewhere.

One unknown is how they are integrated into the corner lighting and if that is controlled by a lighting module (likely) that you'll need to source additionally. Fortunately or unfortunately, cars are getting more complex and I'm pretty confident that even once you have all the hardware, you're going to have to take it to somebody with a DAS machine to code the car to accept the hardware. If one of you has a good relationship with a dealer tech, or more likely, an independent mechanic, they can probably tell you what's involved.

I am still trying to gather all puzzles together. What I know so far is that swapping headlamps should be fine on GL 2007-12. The control unit should be reprogrammed with MBStar. Supposedly, there is no need to add new control unit. The unit that is in the car now should be able to work with Bi Xenon headlamps. Now, I am looking for the forth connector/harness to the HID headlamp to finish the wiring. The diference between Halogen and bi Xenon is that bi Xenon has an additional 4th connector for ballast which has four pins. I think that two pins are used to power the ballast and other two to control leveling system. Ideally, I'd like to get the wires from end to end. I have access to MBStar and should be able to reprogram it on my own. I also heard that others were able to reprogram at dealer for about $100. I hope I am on the right track.

Any updates?

I know that Harris did the conversion. Used Xenons are pretty easy to find on Ebay.

I also know about that but he does not share the details on wiring. I found out which connector is missing. The picture is attached. I heard that these connectors are used on different models as well.

Now, I need to figure out on how the wiring should be done. I am not good in electric stuff and don't want to make any mistakes. I hope to find out where the other end of the wires from this connector should go. This connector has 4 pins. I believe 2 for ballast and 2 for leveling control. There is a wiring diagram available in WIS but it is still difficult for me to locate the physical place. Let me know if you can figure it out.

I haven't really dug into the system (I don't even know what WIS is). From my understanding of his other posts, the sensors and everything are already in all of the cars, and it's a matter of linking up that wire in there somewhere.

How long is the wire attached to the plug?

I also sent him a PM/email to see if he had any other information...so far nothing yet back from him.

I don't actually own a GL yet, so I can't go in there to dig around. Is the other end of the 4th connector just wires? Is it a plug? Perhaps there is a loose wire that runs back hanging out somewhere tied down?

Anyone have a GL with the HIDs that can assist? Or better yet a MB rep that can help out?

I thought I would bump this. I pick up my GL on Friday, and I want to do the HID conversion relatively soon.

As a backup, I know I can do the HID bulb swap using the halogen housings, but I like the idea of the HID high-low beams and a "proper" xenon setup.

Vlad, do you want to post the wiring diagram from WIS?

I did some progress.

First, I found out that the 4th connector is possible to get from dealer for $4 a piece. The part #203 545 03 28. I paid $35 for only finding out about it. This way you will be able to connect the 4th connector on the headlamp.

Secondly, you better buy the headlamp that comes with one module. Headlamps parts numbers re #1648205159 for the left and 1648205259 for the right headlamp. You will need to wire correctly somewhere in front fuse box that under the hood. You may also need to wire somewhere in the fuse box under the glove box. This is what I am trying to figure out.

I feel I am close but not done yet. I added all related to wiring articles from WIS that I picked. I am not sure which diagram will be appropriate. WIS may have more diagrams. I can look for more. It looks like that the wiring should be somewhere with N71 in the front fuse box if I remember correctly. Please let me know if you can figure out the wiring correctly.

After wiring, the car should be reprogrammed which relatively easy if you have Star diagnostic tool.

Awesome. I'm no pro with these diagrams, but I will take a look. I think even when Haris did it, he just paid a shop $500 to do all the troubleshooting on the fuses/electrical....so I'm not sure he would be a ton of help either.

How long are the 4th connector wires? Is this something we need to snake through the interior or something?

I believe most of the wires will be under the hood and possibly some of them will go into the fuse box under the glove box - front passenger side. I am not positive that it even will have to go there. I am getting two different thoughts about it. I don't know yet how long the wire will be. The left headlamp wire may be longer since the front fuse box on the right side.

Your part number description of the headlamp assemblies is interesting to me. All of the used ones I see on Ebay have different part numbers, and different numbers from the ones you list here.

Which ones do you have? What year is yours?

It does not have to be the same. You can see the headlamp I was talking about from here - http://www.ebay.com/itm/07-08-09-10-MERCEDES-GL-LEFT-RIGHT-EURO-STYLE-XENON-Headlight-EXCELLENT-J2-11LR-/200920691642?pt=Motors_Car_Truck_Parts_Accessories&hash=item2ec7ce73ba&vxp=mtr
The most important is that headlamp should be with one module versus two. The other headlamp will require to add additional sensors to the car which makes this job more complex but you will not gain much from it.