New tech... New failure modes. Headlight this time
Thread Starter
Senior Member
Joined: Oct 2016
Posts: 289
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E220d
New tech... New failure modes. Headlight this time
Driving to work in rain today and after about an hour I got two warnings come up. Intelligent light system inoperative and at same time a lamp symbol with Right Hand Dipped underneath. Thought that right front light had failed. Pulled close to car in front whilst waiting at lights and all my lights looked fine in reflection of their boot. Tried main beam and only left side got brighter. Okay I thought, I can live with that and get it sorted at my leisure.
Only later, when I switched car off and got out to look at front, the DRLs were both on but the right main light was also fully illuminated (two DRL strips, two smaller light units and the main headlight). Didn't matter where light switch was it remained lit. Locked car and waited for delayed lights to go off. All other lights went out but right hand unit stayed fully lit on dipped mains. Never known a light to fail on before. Imaging it would have drained battery bloody quickly.
Went back to check an hour later and light was off. Turned car on and faults had cleared and all was well. But saw both front lights have fogged up on the inside. Clearly moisture inside them! Not great on a near new car.
Booked in with merc tomorrow to look at that and a long list of other niggles. This if now the least reliable car I've had in 15 years although they are almost all electrical or trim related thankfully.
Only later, when I switched car off and got out to look at front, the DRLs were both on but the right main light was also fully illuminated (two DRL strips, two smaller light units and the main headlight). Didn't matter where light switch was it remained lit. Locked car and waited for delayed lights to go off. All other lights went out but right hand unit stayed fully lit on dipped mains. Never known a light to fail on before. Imaging it would have drained battery bloody quickly.
Went back to check an hour later and light was off. Turned car on and faults had cleared and all was well. But saw both front lights have fogged up on the inside. Clearly moisture inside them! Not great on a near new car.
Booked in with merc tomorrow to look at that and a long list of other niggles. This if now the least reliable car I've had in 15 years although they are almost all electrical or trim related thankfully.
Member
Joined: Aug 2016
Posts: 139
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From: Redondo Beach
20 E450 Luxury
Sorry to hear of such a hassle. We buy a car and a computer system these days, that is true.
I remember the W212 early on was full of little quality bugs as was the first "C" class after the 190E. Early adopter syndrome is unfortunately a real pain at times. Sometimes design issues crop up, but often sometimes just assembly line issues.
I have heard these new CAN bus control networks are sensitive to their fiber optic cables getting pinched or plug assemblies failing. Fiber optic is a very exacting (mass) assembly process. Think of the numbers involved. When all goes right one never will have a problem with them, but if damaged or defective, then intermittent and strange effects are possible.
Over time, such problems ought to become less frequent. For now, we hope they can trace these faults in the field efficiently!
I remember the W212 early on was full of little quality bugs as was the first "C" class after the 190E. Early adopter syndrome is unfortunately a real pain at times. Sometimes design issues crop up, but often sometimes just assembly line issues.
I have heard these new CAN bus control networks are sensitive to their fiber optic cables getting pinched or plug assemblies failing. Fiber optic is a very exacting (mass) assembly process. Think of the numbers involved. When all goes right one never will have a problem with them, but if damaged or defective, then intermittent and strange effects are possible.
Over time, such problems ought to become less frequent. For now, we hope they can trace these faults in the field efficiently!
MBWorld Fanatic!
Joined: Oct 2014
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From: WI
17 E43; 21 GLS580
A little fogging is OK, particularly in cold wet weather. If water pools in the lamp a dealer visit is necessary. On occasion, the headlights will warn about one thing or the other particularly at startup. As you figured out the headlights will be operating "normally" but for some reason or the other some particular "function" of the headlights will be disabled (humidity, car level at startup, etc.). DO NOT WORRY!!! In the overwhelming majority of cases the "fault" resolves on its own and goes back to normal after a little warming up of the system. On very rare occasions a "reboot" (turning the car off and back on) is necessary. The lights always work in "dumb mode" so you will never be "lightless". If you ever have a fault that will not go away, simply put them in manual mode a flick the high beams on and off manually. Another annoying "beep" thing you will soon discover is when you drive in snow or sleet and the all the auto drive, brake and handling doodles switch off because the sensors are covered with snow or ice. As you well pointed out all the electronic doodads come with some annoyances, however, MB has worked very hard to make sure that all the major essential components are fool proof.
Thread Starter
Senior Member
Joined: Oct 2016
Posts: 289
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E220d
They didn't work hard enough. Car needs new light control unit. Dealer has no clue how long it's going to take to get it (rare failure I guess). What you said about warm up/start up etc didn't apply, I'd been driving for over an hour before the fault was thrown and it was already in dumb (non adaptive) mode.
MBWorld Fanatic!
Joined: Oct 2014
Posts: 4,524
Likes: 1,181
From: WI
17 E43; 21 GLS580
They didn't work hard enough. Car needs new light control unit. Dealer has no clue how long it's going to take to get it (rare failure I guess). What you said about warm up/start up etc didn't apply, I'd been driving for over an hour before the fault was thrown and it was already in dumb (non adaptive) mode.
Sorry to hear that, the new intelligent headlights are a complete new redesign that goes farther than the old system. Hopefully your problem will be an isolated one. Crossing my fingers since my car will have them too! Furthermore, each of those headlamps probably costs a very pretty penny. Let us know how the issue evolves, I wonder if the headlamp computer control is part of the headlamps or on a separate computer module.
