Hay guys,
i have an 02 ml500, 163km
left headlight all of a sudden stop working??
when i turn the lights on i hear a ticking sound...
checked the hid bulb(replaced new 10k) and ballast and fuses... all checked ok
im lost right now, should i get a new left headlight assembly...
do i have to a reset??
anyone have an ideas???

 

Sounds like the igniter has gone bad

 

As KarlBenz said, the clicking noise might be the igniter. You might try taking a look around the headlight assembly and associated equipment at night to see if you see any external arching as that might be the source of your 'clicking' sound.

 

when u say ignitor, u mean the ballast right....
I did switched the ballast and bulb from the right side and even put a new ballast and bulb, both working fine
still no light... i hear a ticking sound but not from the ballast...
i dont think ders power going to ballast...
switched the fuses to new ones still no light...

 

Try and locate where the 'clicking' sound is coming from. Like I said before, try and do this at night when it is dark. The 'clicking' sound might be arching from wires or anything in the HID headlight circuit. You will see this in the dark or at least you should if it is arching. If you don't see any arching, try and locate the sound. Unfortunately I do not have HID/Xenon lights myself, but I do work on electronics and you will find the same principles used there.
You have 2 units that feed the lamp. First, 1-Xenon Headlamp Control Module and then 2-Xenon Headlamp Ignition Module. The bulb is connected directly to the Ignition Module according to the wiring diagram. There is a PINK wire connected to the Control Module that comes from fuses 35 for the right headlight and 34 for the left. If you have power on the pink wires at the headlights, then of course your fuses are good. You must then have an issue between the Control and Ignition modules. If you have a meter and are checking voltages, be careful in this area as you will be dealing with high voltages that can and will ZAP you if you are the better ground! Looking at a diagram like I am, that doesn’t tell me what it actually looks like under the hood! It shows that the 2 modules are located in the “Headlamp Unit”. Also check for any connectors in the circuit back to the fuse. I have found that sometimes the pins in these connectors get corroded and even though you might actually measure 12 volts, the corrosion is enough to limit the current flow. What this will do is supply the 12 volts, but it is not enough for the igniter to acutely ignite the bulb and thus it clicks trying to continuously ignite the bulb. This can happen on other things that require some current to make it work like fans for example. There really shouldn’t be anything else that could cause the problem other than a nicked or cut wire. According to the wiring diagram there isn’t anything after the fuse. One last thing, if the brights don’t work on as well then you might or should have a grounding problem. Both bulbs use the same ground.
I hope this gets you closer to solving this problem

 

ok no arching
but i did feel where the clicking is coming from...
i see a relay inside the light assemble...
would dat be the issue??
do i have to replace it???

 

OK, so this 'relay' is connected before the 'ballast', right? If so, this would be the 'Control Module'. You said before that you swapped bulbs and ballasts, was that just those components or did you swap the whole head lamp assembly? If you just swapped components, try swapping this 'relay' (Control Module). If the problem moves, then I think you know that your Control Module is bad. If it doesn't, check to see if the brights work on the left side or the fog lights. If the brights and or the fog lights are not working as well, then you have a grounding problem. That would be the BROWN wire on pin E at the connector to the headlight. The other end of the BROWN wire is supposed to be connected somewhere behind the left headlight assembly to the chassis/body. Check this connection as well. If the brights are working, then I would take a close look inside the connector to the headlight assembly and look at the pins closely. Look to see if all the pins are nice and shiny or metallic looking. If you have any that look black or maybe a greenish blue color especially on pin H, the PINK wire, then you have had arching or corrosion that has taken place and is building up resistance and not allowing the full current required to get to the modules to light the bulb, most likely causing the 'clicking' sound from the Control Module. If you don't find any issues at the headlight pull fuse 34 in the engine compartment fuse box and look for this kind of discoloration in the socket for fuse 34. If that is good then check the other end of the PINK, HOT, wire, on connector ML/A pin 9 on the bottom of the fuse box. ML/A-9 is for the left headlight only. Hopefully you will have found the problem before you get to this point, as this is not a fun proposition as most of the wires that are connected here are just the right length and won’t alow you to maneuver the fuse box much to try and find the connector you want to check! Again, if you have to, you would be looking for the same discoloration as before.
If you do find corrosion/arching, the best way to clean the connection is to use ’lapping compound’. You should be able to find this in any auto parts store. Lapping compound is used to seat valves in a cylinder head. It is an abrasive compound/paste in a tube much like toothpaste, just more abrasive. You would take some of this paste and smear it on the male pins. Then insert the pins in the connector several time. Keep doing this until you get a nice and shiny metallic look to the male and female pins. Once they are nice and shiny use some electrical contact cleaner spray to clean out any residual paste. You should now have very connections!

One not of caution on the contact cleaner. Check the container to see if it says something about not attacking plastics. Some contact cleaners use chemicals that attack some plastics, leaving you with clean wires and pins but a connector that will crumble in your hands!

According to the wiring diagram, you should find it! There is nothing else that I can see that would cause just the left headlight to not work. The wiring is supposed to be a straight shot from the fuse box to the headlight. Anything before the fuse box would cause both lights to not work.
Good luck!

 

I have a 2004 ML500.
Sounds like I have exactly the same problem as Momo. I've changed the HID bulb on the driver's side to no avail. I have replaced all the bulbs (100/each for the HIDs) and swapped the ballasts. Same problem.

I believe it isn't a grounding problem, since my high beam on the driver's side operates normally, as does the HID low beam on the passenger side. Only the HID is out on the driver's side. It's interesting to note that if the headlights are in bright mode when turned on, the 10 clicks heard on the driver's side also flash the bright beam, on the driver's side so I believe the relay controls the power to the bright beam as well as the HID beam and is working. And is receiving power.

Swapping the "control module" that is the part with the relay inside isn't feasible since the wiring is all inside and around the bright and running beam bulbs and holders. I'm not sure I would trust that even to a trained factory tech, especially with the poor quality service I've received from my local Autobahn motors MB dealer. Swapping the Headlamp modules isn't an option since they are mirror images of each other and won't fit, and to remove them requires the removal of the front bumper, not a project for your weekend mechanic.

Also some misinformation in the other posts for at least my ML: Fuse 34 and 35 aren't populated. The fuses labeled "left beam" and "right beam" come from F20 and F21 in the footwel fusebox. F20 and F21 power only the bright beams and the bright indicator. To run the HID headlights, I don't need either F20 or F21. The HID headlight power is coming from somewhere else. I don't have a clue where, as yet.

With the bright switch activated, I have power on both F20 and F21 in the footwell, and the fuses are good, but I have no power on the passenger side bright bulb. It's got to be either an open wire along the way, or the relay that controls the bright beam on the passenger side has failed. Or something else.

It's also interesting to note that Momo's symptom is exactly the same as mine. I'd love to hear his solution. As it kind of sounds like a frequently occurring problem. Any ideas are most welcome: I will be admitting defeat shortly and will take it to an electronics diagnostic center a few towns over.

 

Check the igniter. It is the black small box behind the bulb
Also read this thread it will give you some tips
https://mbworld.org/forums/m-class-w...t-working.html

 

Thanks, Art. Like Momo said, both he and I swapped the "igniter" which may also be called the "ballast" left and right side with no change in symptom.

I went to 4 non-dealer Mercedes "experts" today to see what I could find out. 3 of the 4 told me that I had to have new light modules (maybe not the correct terminology, but the part that houses both bulbs, the "igniter" "ballast", the relay, and some other unknown components). Very expensive, but a typical response from a "module swap" mentality. I think they were pretty clueless. And I don't think the problem is in that module (it may prove to be the clicking relay, so the jury's still out on that one).

One non dealer "expert" spent 2 hours with me, looking at his software repair manual wiring diagrams. He and I couldn't find the fuse location for the HID bulbs. He said that sometimes Mercedes "hides" information from the 3rd party repair personnel. We traced the wire from the HID lamp through 2 "activity modules" where it disappeared. So the fuse is still hidden from our sight.

Momo said he believes that the HID bulb is not receiving power. I believe the same. My repair guy said that he would trace the wire from the switch on the steering column through the 2 activity modules to the bulb. (He said that sometimes "activity modules" are nothing but relays). I will take the van to him Monday unless I discover something in the meantime. If I do, and if his information proves useful, I will give him at least a couple hundred. Those guys you need to keep in business.

I will check your link on the 320 now. Thanks eversomuch for the response!!