Indicator Problem - C Class W203

[jon pollard]

C-Class W203

Computer indicates that front left indicator bulb needs replacing and that system is using a substitute bulb - System is most definately not using a substitute bulb to indicate with despite what it says!

Front nearside bulb is OK (I've checked it), bulb housing is OK (I've swapped it with the off side), fuses all appear to be OK; but still no indicator on front nearside.

Any suggestions?

 

[mbserran]

C-Class W203

Computer indicates that front left indicator bulb needs replacing and that system is using a substitute bulb - System is most definately not using a substitute bulb to indicate with despite what it says!

Front nearside bulb is OK (I've checked it), bulb housing is OK (I've swapped it with the off side), fuses all appear to be OK; but still no indicator on front nearside.

Any suggestions?

I have exactly the same problem in the same kind of car. In fact the car is using a substitute bulb. It is the fog light, that is used in the fashion of an indicator one. That's I suppose for still keeping active the indication functionality in the car in order for the other drivers to see your indications. But with regard to the solution to this problem, I still do not have an answer. I have done the same (swapped the bulbs, even the housing, and no way). I haven't found the fuse because I think is an electronical one. I have polished the contacts of the bulb housing, just in case they were not working fine, but with the same result. In any case I keep trying, so I'll let you know if I get an answer. What I've found out is a thread making reference to a factory housing failure in some models of C-Class W203 (year 2001). I do not know if it is true but I know that we are not the only ones with the same kind of problem. Probably one of those that suffered it could give us a solution.

 

[piestore]

203 indicator fault

Hi

fault is in the headlight there should be indications of burning on the bulb holder there is a mod to a hard wired bulb holder should get it on warrenty even if the car is outside warrenty period the mod kit is about 35 quid per side which is outragous when you see what is in it but it is a lot cheaoer than buying a headlight

goodluck

 

[mbserran]

Hi

fault is in the headlight there should be indications of burning on the bulb holder there is a mod to a hard wired bulb holder should get it on warrenty even if the car is outside warrenty period the mod kit is about 35 quid per side which is outragous when you see what is in it but it is a lot cheaoer than buying a headlight

goodluck

You were right. The problem was in the headlight contacts. By opening a little bit the bulb holder contacts and then turning arround one another side the bulb holder over its position in the headlamp you will achieve the holder contacts to clean the headlamp ones. You'll get a bunch of white dust for sure. After that if you fit the holder in its position the indicator should work again. Hope it helps! It helped me!

 

[vinay.chapaneri]

indicator bulb

guys i had the same problem , mine was not too bad, what i did was to got to a merc specialist and got a buld holder(housing from him) about £4.99 then i just cleaned the inside of the housing where the holder was, both the copper connections where fine, however the garage told me that before refitting i should slightly extend the contacts outwards this would prevent "arcing " when the indicator is switched on, i have done so nad the indicator works fine. however the fault has cleared but will remain in the computers memory.

 

[VKS1]

I had the same problem and just used a little sandpaper on the contacts and put a very thin layer of solder over it and pulled the pins out about 2mm on each side, working fine and saved me 50 on fitting the aftermarket kit on each side.

 

[Yadagi]

Hi all you lovely people,
I am bumping this thread as it relates to my problem, and i'm hoping someone can help me , as you have always done in the past.

My right front indicator started flashing double time a few day's ago, and the error message said that the substitute bulb was being used, we( hubby and i) changed the bulb , but it was still not working, and then swapped the working one on the left for the right , thinking it might be the bulb holder, and that did not work either.

We have put them both back in their original position, and now neither of the indicators working!!!

The bulbs seem fine and and the contacts on both bulb holders , which are wireless , push in and turn type are ok , although one of the contacts on each holder needed a bit of cleaning ( used an emery nail file) while the other was very clean .

We have a mechanic friend coming round tonight to have a look, any ideas please would be greatly appreciated.
I have a 2002 C180 , ( W203 I think )

P.S might be related , but for about 2 years the intermittant wiper, was not working on rain sensor, then it started working by itself about 2 months ago !!!,
a
A few weeks later the headlights went off when switched to Auto, while driving through Epping Forest one evening!!!, but then started working again but the headlights dont work now if switched to the ON position .As they are working on Auto I haven't done anything about it.
Now this problem, has come up and wondered if it could be a relay /electric problem as have seen some threads talking about the relay.
Thanks again

 

[television]

The lighting module could be faulty, as could a SAM it needs to go on STAR to see what is happening

 

[Alex Crow]

if in addition to the indicator problem, the headlamps do not work in the ON position, you could possibly have a failing front sam unit. this could tie in with the occasional wiper fault too. this is assuming the front indicator bulb holders ARE ok, which you have asserted. i suggest you have a diagnostic session with a true specialist who is familiar with these cars and has star at his/her disposal.

 

[Yadagi]

Thank you so far for the quick replies.

Hope you do not mind me asking, but what is a SAM?

 

[Alex Crow]

S.A.M unit = Signal Aquisition and Activation Module. basically it is a nerve center for various functions on the car - eg when you turn on the headlamps at the headlamp switch, the sam unit turns on the lights. same with the wipers. they fail fairly often on these cars, and cost around £280, but you really need a proper diagnosis!

 

[Yadagi]

Ok found out what the Sam is, waiting for the mechanic to come round, will let you know!

Any idea though why the left side light bulb holder was working until we swapped it over to the right side and then it stopped working on both sides?
Thank you

 

[Yadagi]

Can anyone tell me where the Sam is located?

 

[Alex Crow]

sam is integral to the front fuse box, it is the unit with the fuses and realys mounted on top adjacent to the brake servo.

beware the fickle substitute bulb protocol on these cars - if you so much as undo a bulb holder any time the ignition is on then it will not be used by the sam again until the ignition has been off and on again. so have you tried the indicators since??

 

[Yadagi]

Thank you ,
We think we found the SAM, is it located under the bonnet just under the drivers side windscreen. You have to take a plastic cover off , then unhook to clips to get the cover off, the actual module.

There are lots of wires and fuses .The mechanic pulled out one of the plugs and the fan started going!!

We did take the key out of the ignition and reset the malfunction message by turning the key to position 1 then off again. The indicators are still not working.

What I don't understand is why only one was not working at first and now both sides have gone after changing over the bulb holders.?

If we have to get a new SAM do we need to get it programmed to the car?

 

[Alex Crow]

yes, it needs programming. i must stress again the need to get the car properly diagnosed. you have hertfordshire merx in letchworth - is that near you?

 

[television]

As Alex do not just go and buy a SAM for it must be programmed, as you neither side now it does not look SAM related

 

[Yadagi]

Good morning,
Letchworth is not near to me, we are in East Herts, but also close to North London.
If we have to get a SAM , I read somewhere that you can get it programmed to your cars VIN number?

Television , why do you think it is not related to the SAM, any ideas what else it could be.
Thank you again .

 

[television]

I do not think so now as both sides have stopped working, unless you still have the other problems with the headlamps. in this case it could just as well be the Light module at fault.

On these cars plugs should never be pulled while the battery is still connected

 

[Yadagi]

Ok ,
If it is the light module, what do we need to do next.?

The headlamp works fine on the Auto position, does not work on the ON position, and works fine on the dipped beam position, and the foglights work as well, when you pull out the switch.

The bulb holder was pulled out with the ignition in the first position I think.? Have we messed up and need to find a way to reset the fault.
A few weeks ago the back indicator fault came on and when we changed the bulb , at first it wouldn't work, then hubby took the key out and turned it back on and the indicator started working fine.!!