Mercedes Vito w639 main beam lights problem??

[Christosfazer]

Good evening to all community,
There is something weird for me on my car!I have an w639 vito 109cdi 2009 with 646980 engine!
The vin decoder shows that the car has the code

L04	AUTOMATIC DIM-DIP LIGHT

The switch of the light is the classic light switch as the attached link:

Bloc lumini Mercedes VITO VIANO W639

200 Lei: Ne asumam perfecta functionabilitate a piesei . Piesele vin acompaniate de garantie pe termen de 3 luni de la data achizitionarii ! Compania noastra are de mai mulți ani de vânzare piese originale pentru Audi, VW, Skoda, Seat și alte mărci. Sunte...

anunturi-auto.4tuning.ro

The problem is that i have the car about 4months and yesterday was the third time that the car blown the position bulb!
Another issue for me is that when the car light switch is on 0 the low beam is permanently on and on the dashboard the low beam light (green one) is on!
Is this normal for a car which has the L04 code from factory?
Why the bulb blowns?
If it was a short circuit the bulb should blown maybe immediately and not after 3-4 weeks!do you agree with that?

Hope i helped you with my problem explain!

Regards,
Christos

 

[Ted]

Hi Christos, if it were a short circuit it would not blow the bulbs.
I would just check that the voltage while charging in not above around 14.3-14.4, replace with good quality bulbs, check your headlamp earths, and take it from there.

 

[m80]

A plug in voltmeter would be good to check charge voltage while driving, but they aren't all accurate so checking the voltage with a good DVM and comparing to the plug in meter would give you idea of accuracy and any adjustment you need to allow for.

Check for water ingress to the SAM, inside the under bonnet fuse box. You're issue could be related to a faulty SAM or faulty light switch, but water into the SAM isn't uncommon.
The aren't expensive to buy 2nd hand and will plug and play if you buy 2nd hand.
Be sure to match the replacement part number to the existing.

 

[BIG UN]

Good evening to all community,
There is something weird for me on my car!I have an w639 vito 109cdi 2009 with 646980 engine!
The vin decoder shows that the car has the code

L04	AUTOMATIC DIM-DIP LIGHT

The switch of the light is the classic light switch as the attached link:

Bloc lumini Mercedes VITO VIANO W639

200 Lei: Ne asumam perfecta functionabilitate a piesei . Piesele vin acompaniate de garantie pe termen de 3 luni de la data achizitionarii ! Compania noastra are de mai mulți ani de vânzare piese originale pentru Audi, VW, Skoda, Seat și alte mărci. Sunte...

anunturi-auto.4tuning.ro

Another issue for me is that when the car light switch is on 0 the low beam is permanently on and on the dashboard the low beam light (green one) is on!
Is this normal for a car which has the L04 code


I believe Auto dim dip uses the same sensor as Auto lights, it wasnt a standard option, definitely an optional extra but what puzzles me is that light switch shown hasnt got the auto position and it shows Auxiliary heater does it have that as well??.. The lights should be off when the switch is at 0.
Maybe the issue is with the switch,
You would be much better off getting it on Star as that will find the issue.

 

[Christosfazer]

Hi Christos, if it were a short circuit it would not blow the bulbs.
I would just check that the voltage while charging in not above around 14.3-14.4, replace with good quality bulbs, check your headlamp earths, and take it from there.

Hello Ted and thanks for the quick reply,
If i understood right you mean that maybe my prob is on the alternator...Right?
If there was a problem on the alternator i should have more issues with all the electric!Isnt it right?
I agree with you about the earth contacts and i must check all of them!On the other hand problematic negative = blown and the other bulbs!
Dont know

 

[Christosfazer]

hello Big UN,
Unfortunately the Star doesnt throw any kind of fault!
Yes my car has auxiliary heater

 

[Christosfazer]

A plug in voltmeter would be good to check charge voltage while driving, but they aren't all accurate so checking the voltage with a good DVM and comparing to the plug in meter would give you idea of accuracy and any adjustment you need to allow for.

Check for water ingress to the SAM, inside the under bonnet fuse box. You're issue could be related to a faulty SAM or faulty light switch, but water into the SAM isn't uncommon.
The aren't expensive to buy 2nd hand and will plug and play if you buy 2nd hand.
Be sure to match the replacement part number to the existing.

If there where any fault in SAM i think that it should throw tons of fault codes!Do you agree with that?

 

[m80]

If there where any fault in SAM i think that it should throw tons of fault codes!Do you agree with that?

No, the SAM is a complicated electronic unit that can be confused by a variety of reasons. Common in my limited experience is ingress of moisture, water, into the fuse board enclosure. But spikes can screw 'em also.
For me owning a replacement SAM, of identical ID, even with known faults, is a good strategy.
If you are able to swap out SAM's and remove, or change faults , you can diagnose that as the cause.

I have a spare SAM that has 2 faults (on interior lights and n/s indicator), if my present and healthy SAM is faulty I can prove that the SAM is the issue. That is dependant on the faults being different though.

 

[Ted]

@Christosfazer - best not to guess - either get the charging checked out or get a digital voltmeter to test.
Also, as you say, could definitely be the brown earth wires - there are usually a few of them together on a stud on the inner wing.
Don’t forget it could be cheap bulbs too.
Good luck - it shouldn’t be too hard to track it down.

 

[Christosfazer]

@Christosfazer - best not to guess - either get the charging checked out or get a digital voltmeter to test.
Also, as you say, could definitely be the brown earth wires - there are usually a few of them together on a stud on the inner wing.
Don’t forget it could be cheap bulbs too.
Good luck - it shouldn’t be too hard to track it down.

Ok Ted
I hope to find some free time maybe until Sunday to troubleshoot this problem!
I will keep you posted

Thanks for your advices

 

[Christosfazer]

Good evening to all and sorry for the delay to answer!
I didnt find anything during the troubleshooting!Everything was fine!No shorted cables,grounds and voltages were OK!
I hope that the previous owner has bought bulbs from the LIDL and not the genuine

Thanks for your help