Both Dipped Beam Faults (following replacement bulbs)

[Titch]

Hi,

Hope someone can help...

I have a 54 reg c230k c class saloon. One of the xenon bulbs needed replaced so I changed both myself. They worked fine for a week or so and now I have the "dipped beam" fault on the command screen. The dipped lights will not come on at all.

Ive checked both bulbs and they are working and I've also checked the fuses and they are fine.

I connected a multi meter to read the power to the connector and it's intermittent and they not at all after the car has been running for 2-3 mins. It looks like the computer isn't sending power to the connector cable as its sensing a fault.

I've read previous posts and people say it needs to be activated by the star machine?! Is this correct?

Any help/advice appreciated.

Thanks

 

[brucemillar]

Hmmm

I had similar with both sidelights not working. That was a front SAM that had failed.

You may want to get the car plugged into STAR if you cannot spot anything obvious in the connectors/wiring.

 

[Titch]

It's strange as both were working when installed for a week.

I can't see anything obvious that is loose and then all of a sudden both replacement lights don't work.

I even replaced the old bulbs to see if that worked but it didn't.

I was thinking a relay or something as the power isnt getting to the bulbs to power it, as I said its like the car is stopping it from sending power as it senses a fault or it doesn't recognise the replacement bulbs.

 

[brucemillar]

Titch

I am not the expert and somebody will come along soon who may have some other suggestions. What you describe is what happened to my sidelights. They only had 1.2v at the bulb on both sides. It was the front SAM. I ponced about for ages trying to find a fuse or a relay or dodgy earth took the local Indie less than 2 minutes to show me the SAM error on STAR and he fitted a new one while I was with him - Bingo.

 

[andy27168]

Hi,
I take the car has OEM Xenons?
Where did you say you put the multimeter to check for power, at the Xenon bulb connector?
Were the bulbs OEM or a decentish make?
Personally it sounds like you possible have taken the front SAM out, though without a proper diagnostic it is difficult to say.

 

[Titch]

Hi,

I put the multimeter against the power connector which the bulb fits into.

Thy weren't expensive replacement bulbs, bought from amazon for £20. Guessing they could be the cause of it...! The power pulses to the end connector but after a short time no power what so over.

I'm going to have to put the car into my local Indy for checking over.

Will post an update on outcome once she is back hopefully.

Thank god its summer that's al I'll say!

 

[andy27168]

Hi,,
Have you checked your voltmeter still works? My understanding of a Xenon lamp is that it needs a surge of voltage to strike the lamps, hence the high voltage warning stickers on the headlight or slam panel adjacent to the headlight.

 

[Titch]

By way of an update, car is currently in with Mercedescarspecialist at Ibrox in Scotland for chekcing. They have been mentioned on the forum before so decided to put her into them. Dropped it off this morning 7.45am and told the receptionist the problem. I did expect to speak with a technician... Called back to be told checking the bulbs, wiring, fuses etc...

I just assumed they would connect it to the Star machine and that would diagnose the fault?! I'm sure the guys know what they are doing though.

I also asked them to look at a vibrating passanger seat when I reach around 60-80mph so lets see what they say about that.

Waiting on the dreaded call back with news...

Will update on outcome once I know.

 

[davidsw]

personaly i wouldn't put a meter anywhere near xenons !!

 

[Titch]

Hi,

Garage couldnt diagnose the exact problem and they had an auto electrician look at it as well. They have suggested replacing the full lighting system for £420 which would give me lights again. I told them just to leave it and I would take it else where for a second opinion. Dissappointed with the service and suggestions from what was supposed to be a specialist mercedes garage. They didn't mention the ballast and said it could be a problem with the SAM.

Davidsw - Why not put a voltage meter onto the xenons? I realise they put out a high voltage? Is it because it's dangerous? On the meter, it read 12 volt. My dad is very handy with electrics and we used a cheap meter incase it fried it. No big surge through it.

I stripped off the ballast, opened it up and had a look inside. Doesn't seem to be any damage or burn outs. I think i'm going to purchase a replacement ballast to see if that's the problem.


Anyone any other suggestions?

Thanks,