LED lighting

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Marku

Active Member
Joined
Dec 18, 2012
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808
Car
Viano Ambiente 2.2CDI W639, S-Class 450SE W116
Thought I would replace much of the lighting with LEDs. Everything fine, so far, but for the parking lights. They said they were replacements for the W5W bulbs but it doesn't like them. What should I be fitting?
 
Well it seems that there is no such thing in Mercedes world as an error free led bulb. Looks like the only solution is to fit resistors in the line. That would make it expensive but considering it if only to get rid of the error messages.
 
I put these in my S204 front side and parking lights and did not get an error - but they overheat, the front glass lens melts and they fail. I also tried the error free ones that have sharp edges, but they catch and fall inside when you pull the bulb holder out, so I've given up and gone back to standard bulbs!

However, in the rear lights I have all LED's with the exception of the indicators (where you need a LED suitable flasher relay) and they're fine.
 
Ultraled wedges work fine on my w204 with no errors.
 
Ultraled wedges work fine on my w204 with no errors.

Check that your bulb holders are not melting from these inside....
 
Well it seems that there is no such thing in Mercedes world as an error free led bulb. Looks like the only solution is to fit resistors in the line. That would make it expensive but considering it if only to get rid of the error messages.

Osram resistor kits are about £15 and seem to be really simple to fit. They do heat up also, so you'd need to find a safe place to put them.
 
Does anyone know what the margin for error actually is.

Using some nominal values a W5W at 14 volts will pull 357mA

At what point does the bulb failure warning get triggered. e.g. could you get away with pulling only 300mA without triggering the bulb failure error.

If we knew this information it would be easy to bench test prospective replacement LEDs and know if they were going to work or not.

As an Engineer I'm appalled that in many cases resistor kits are being sold with no designation of intended use. So for example you could end up with a resistor intended for a brake light dissipating 21 Watts to enable a 1 Watt led to function in place of W5W. It's no wonder there are problems with heat. Or does the lamp failure monitor also pick up excessive current as well as too little.
 
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Tried several led bulbs that stated they were canbus error free but have also read that systems in premium marques like Mercedes, BMW, Audi etc are much more particular. I think you can get a BMW specific resistor kit. Surely it wouldn't need to be that sensitive as the difference between an led and an incandescent must be substantial. I take it that every bulb would require a resistor. The resistor kits I have seen have no designation.
 
Every bulb would need a resistor but if MB's are that particular surely the resistor has to be a different value depending on the wattage of the incandescent lamp that is being replaced. The whole thing seems a mess to me I would much rather MB hadn't fitted a bulb failure system.
 
Just find a way of safely mounting the original bulb somewhere where it won’t touch or melt anything, and use a ‘non canbus compatible’ led.
Resistance will be perfect, no calculations or uncertainty, and the minimum amount of heat needed so the bulb failure detection isn’t triggered.
 
It's generally down to how they are installed and handled rather than faulty units. I sold nearly 700 pairs, with only a handful of actual faulty units. Infact I'm still on the same pair I fitted to my W202 in 2010.

Make sure the 'follow me home' lighting feature is off, don't have your lights set to auto and when installing them make sure they do not touch anything.
 
Check that your bulb holders are not melting from these inside....

Been fine since march 16.
I've read a lot about LEDs heating up but as far as I can tell these don't
 
LEDs heat up, so do standard bulbs, a decent quality LED unit won't melt anything.
 
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It's not the LED that gets to that level of heat, it is the 'error free' resistor that's on it.

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I have the Phillips white vision w5w’s in my front sidelights, they are good it’s a nice light. Gave up on getting LED’s to work in there. I thought if you have to have a stupid resistor to burn power to fool the bulb warning you might as well just have normal bulbs. I’d rather not have the bulb warning system tbh but there doesn’t seem to be a way to disable it.
 
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It's not the LED that gets to that level of heat, it is the 'error free' resistor that's on it.

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Not true, LEDs do generate heat. touch a set of non-Canbus resistor units and you will see.
 
Not true, LEDs do generate heat. touch a set of non-Canbus resistor units and you will see.
OK... but they do usually run at a lower temperature in comparison to equivalent halogen bulbs, it is the resistors which are causing heat issues (melting lenses/bulb holders) in the canbus LED's, not the actual LED's themselves IMO.

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Given up on finding an LED for the side lights and gone with halogen. Interesting that the system monitors everything not just the CANBUS error. Had the diagnostic light come on Thursday so had a diagnostic done on Friday. Everything I had done recently all my tinkering with the lights, including the interior, were all logged quite a list of things. Wasn't anything I had done it was logged as excessive boost on acceleration. Apparently an air leak on the intake.
 

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