CLS 350 Flickering headlights - can anyone help?

[kristyd]

I have a 2006 CLS 350 and I have just installed two brand new Xenon headlight units, D2S H7's to replace the old ones. However, about 10 seconds after I switch on the lights, they start flickering, sometimes even switching themselves off completely. They are both brand new Hella units (D2S H7 SAE HG HR 03 SSB 490 VOL H7) and both units are showing the same flickering problems. The old ones were actually working fine, which suggests that the problem is with the new units themselves. The car has a brand new battery. The voltage is fine. Any suggestions would be much appreciated. Thanks.

[Paddymcc]

Would it be a problem with the ballast that you sit the bulb into?

[kristyd]

Many thanks for your reply. I have read on a number of forums that the ballast could be the problem with flickering lights. But the ballast is part of the headlight unit, is that correct? And if so, that is what confuses me as they are two brand new units and they are both displaying the same problem. Could both new units have the same problem? This is what confuses me mostly, they are brand new units from Hella. Has they been a software upgrade or something that is conflicting with these units?

[Paddymcc]

No the ballast on these plugs into the rear of the bulb and can be completely removed from the car when changing bulbs.

They are shared with land rover, BMW and rover when I was checking out some spares. They cost about £25 new on eBay.

[msduk]

Check your front tyre pressures

[mybrainhurts]

I've had a couple of occasions when these bulbs flickered. They gradually got worse until they went out, then reignited when switched off and on.

In both cases, a new bulb fixed it.

I suggest your new bulbs are faulty. Do you have access to another car to try them out?

PS...I've used £10 ones for my replacements and these worked perfectly for a long time.

Edit...I've also replaced an Osram bulb with another Osram bulb. The new one appears to have been a fake, the build quality noticeably worse when placed side by side for comparison. Even if it was a fake, it worked without problems.

Edited by mybrainhurts on Wednesday 23 March 01:07

[kristyd]

Hi guys,

Thanks for all of your suggestions. After weeks of pulling my hair out, the solution turns out to be very simple, The official Benz garage were wrong!!!!

I went to an official authorised Benz garage to get a quote to replace the lights. Using my chassis number, they logged into "Benz Germany" which apparently pulled up the exact specifications for my particular car, which included Xenon light units. Their quote broke down as follows €1,265.40 per light unit, €179.20 labour and €569.13 VAT - Total quotation €3,279.29.

I used their parts reference to order genuine Hella light units direct from an independent supplier, cost €692.01 each and when fitted, it resulted in the flickering problem with the lights.

I called in an independent auto electrician who plugged in and told me that I had the wrong light units for my car!! Basically, he said if there is any variation in the voltage going to the Xenon units then they would switch off, which produced this cycle of flickering on and off. My car was not set up for these Xenon units.

So it turns out that the official Benz garage quoted for the completely wrong headlights. My car takes a standard Halogen unit and NOT a XENON unit. So I returned the Xenon units and purchased the standard halogen ones, cost per light unit €236.86. Total costs broke down as follows: Lights x 2 - €473.72, auto electrician - €100, mechanic - €120 - total cost of the job €693.72, thats €2,585.57 LESS than the official Benz garage was quoting me!! Lights working perfectly!!!!

In conclusion then, I definitely would not trust the official authorised Benz dealer, even though they claim to have access to the exact specifications of my car! When replacing parts in future, I will remove them first and make sure that I order the exact replacement parts. And finally, even though there was a lot of hair pulling, I have managed to save more than €2,500 by doing the leg work myself.

Thanks again guys.