LED's Buyer Beware!!!!!

[television]

The SAM does not come into it either, that only a means of storing component information where components can be called up. You can have a lamp monitoring system as we did on the 124 with no CAN and no SAM

 

[television]

Do we blame the postman when he brings a letter telling you some bad news ?
Do we blame our telephone provider when it rings to tell us some bad news ?

Do we blame the fire alarm when it tells us the house is burning down ??

 

[V6Matty]

i blame antz every time i fart does that help?? :lol:

 

[television]

i blame antz every time i fart does that help?? :lol:

But you cannot get that into a CAN

 

[turbopete]

im obviously a little more out of touch with how these CAN BUS things work than I thought! i was aware that they were a data thing, and that somehow they log bulb errors (both blown AND insifficient current draw) BUT im a little puzzled how ithe CAN knows to put the warnings on etc. does it take a reading of current draw from somewhere when a given circuit is used, , send the signal to the SAM, which then processes the info and sends it to put up the appropriate warning signal, Via CAN? i really need to get myself up to date again!

 

[turbopete]

i blame antz every time i fart does that help?? :lol:

I blame baked beans

But you cannot get that into a CAN

the beans come FROM a CAN though :lol::lol:

 

[television]

im obviously a little more out of touch with how these CAN BUS things work than I thought! i was aware that they were a data thing, and that somehow they log bulb errors (both blown AND insifficient current draw) BUT im a little puzzled how ithe CAN knows to put the warnings on etc. does it take a reading of current draw from somewhere when a given circuit is used, , send the signal to the SAM, which then processes the info and sends it to put up the appropriate warning signal, Via CAN? i really need to get myself up to date again!

Pete, The EIS is the master of the CAN system, all electronic components have to be working correctly, so the EIS sends out a message over CAN C to all important things first, and waits for the return message all OK. This CAN is the very high speed one and CAN C components are checked first, once all these self checks have been done, then CAN B, the body CAN starts, if CAN C is busy, then CAN B waits till it all died down a bit on CAN C, or goes it goes quiet.

The CAN knows nothing more than the postman knows about what is in a letter that he brings.

 

[beccy]

JG007, whatever is wrong/ happened I hope that the part we located for you gets fitted and works perfectly. Keep us updated on the outcome.

Fingers are crossed!

 

[jg007]

Just returned from Mercedes garage.

Actually Miffy CAN BUS works on the watts used, not on the voltage drop (I was corrected by the MB technician) and as has been pointed out, it is not the CAN BUS faulting, but the SAM unit, which communicates via the CAN BUS.

The reason for the failure

The explanation is the earth side return of the lighting circuit to the SAM unit is the reason why the lighting circuit in the front SAM was blown.

Whilst it is quite obvious there are a wealth of passionate owners, it does rather feel like i am being jumped on.

Perhaps don't shoot the messenger applies here...

Thank you all for the lively debate and the corrections where appropriate, but the intent when i first posted still remains, i would not want anyone else to have to go through the cost of this exercise unnecessarily, so...

If you fit replacement LED's that are not CAN BUS/SAM friendly, the return earth voltage will adversely affect your SAM unit, eventually leading to a failure.

 

[whitenemesis]

The question still remains, why has this only happened to you? No one else has ever raised this issue, despite plenty having problems with leds giving bulb error messages.

 

[drmw]

Just returned from Mercedes garage.

Actually Miffy CAN BUS works on the watts used, not on the voltage drop (I was corrected by the MB technician) and as has been pointed out, it is not the CAN BUS faulting, but the SAM unit, which communicates via the CAN BUS.

The reason for the failure

The explanation is the earth side return of the lighting circuit to the SAM unit is the reason why the lighting circuit in the front SAM was blown.

Whilst it is quite obvious there are a wealth of passionate owners, it does rather feel like i am being jumped on.

Perhaps don't shoot the messenger applies here...

Thank you all for the lively debate and the corrections where appropriate, but the intent when i first posted still remains, i would not want anyone else to have to go through the cost of this exercise unnecessarily, so...

If you fit replacement LED's that are not CAN BUS/SAM friendly, the return earth voltage will adversely affect your SAM unit, eventually leading to a failure.

Please don't think anyone is jumping on you - as you've shown, the problem wasn't what you had been told, so the only person that needs jumping on was the guy that told you!

We'll no doubt now get a further round of views on the SAM culprit but again, nobody's getting at you.

A lot of members here (me included) have fallen foul of garages spotting a symptom rather than the cause which can end up being very expensive so each is only trying to help prevent that happening

 

[jg007]

The garage similarly asked the same question and the only answer that they and MB thought made any sense was that the from SAM unit in my car, that faulted, was a very early one, which was superceded fairly quickly, therefore the number of "incidents" would always have been fairly small...

 

[Miffy]

Well the only real advice is to fit the appropriate oem style bulbs. I still disagree (with your tech) on the LED being the cause of frying your SAM

 

[Miffy]

The garage similarly asked the same question and the only answer that they and MB thought made any sense was that the from SAM unit in my car, that faulted, was a very early one, which was superceded fairly quickly, therefore the number of "incidents" would always have been fairly small...

do you have the part number of your fried sam, I will check on MB Parts for revisions

 

[jg007]

Actually I can do that for you, i have all the superceded part numbers for the front SAM in chronological order from MB database



I hope this helps others

 

[Miffy]

Thanks, there were, as you correctly pointed out quite a few revisions, but the last one clearly states to use up existing stock before moving to the new SAM so I doubt they were revised for the reasons your tech has claimed.

Its going to remain a he said / she said situation I am afraid. But your's is still the only case we have seen on this forum of this happening. Thats not to say its not happened to others though.

 

[jg007]

Undoubtedly it will be a he said she said discussion, nut i can only report on what i do know.
Not faulty before LED's - health checked by MB main dealer - 2 days later fitted LED's faults started...removed LED's number of faults reduced...

I suspect there is no way of categorically attributing it to a specific event/aspect, but i think that a little faith goes a long way.

One of the reasons that they were revised was due to the wing mirror wires breaking when the "close on lock command" was activated; MB had to fix a lot of broke wing mirrors and a number of boot brake light wires for the same reason.
Hence in later models of the SAM, the ability to program the close on lock was deactivated in the SAM, whilst still continuing to appearing in the dash display.

 

[television]

If you fit replacement LED's that are not CAN BUS/SAM friendly, the return earth voltage will adversely affect your SAM unit, eventually leading to a failure.

Lets put it this way, if a normal bulb is making a poor contact, then all of us know that this will illuminate the bulb out warning, nothing to do with any ground, there is no ground return, ground is used to complete the lamp circuit.

The measurement of a bulb is not in Watts, Watts is the dissipation of power derived from the voltage x current, the only thing that can be measured is the current flowing in that circuit.

Now if a normal bulb fails, then no current flowing in that circuit, fit a LED with no ballast and only a few milli amps are flowing.

So by your reckoning a SAM would fail if a bulb blew as they are both a low or no current flowing situation. This is the part that makes what you have been told just so wrong .

 

[Miffy]

Lets all try and remember he is retelling what his "tech" has said. Personally I think this is a case of a faulty sam, and the "tech" thinking of the best excuse to sell to his customer.

 

[Miffy]

whose the best indie in manchester? maybe the OP needs to try somewhere else?