Mercedes W203 coupe no brake lights.

[amazighman]

Hi all.

My 2006 W203 C220 CDI coupe has developed a strange problem.

The rear brake lights dont work , so the substitute ones at very top of the rear light cluster are working instead , the third brake light in the tailgate is working too.

The bulbs are fine , there was a warning on dash Right brake light , but no warning anymore , however no brake lights.

Any idea? These do have a brake light switch? Or it is sam module issue?

 

[markjay]

They do have a brake light switch, but if it was faulty than none of the brake lights would work - but you are saying that the spare brake light bulbs are illuminating when stepping on the brake pedal?

 

[markjay]

Have you replaced both brake light bulbs with new bulbs? Or did you just 'test' the old bulbs?

 

[markjay]

And, is the battery fully charged?

At any rate, you may need to take the car to a specialist who has STAR, or invest in a code scanner for MB e.g. iCarsoft MB v2.0.

 

[amazighman]

Hi , replaced bulbs with new , still nothing , battery is 2 months old genuine and fully charged.

I have Icarsoft and it only says right brake bulb defective.

The problem started few days ago , got a message on the dash about Right brake bulb , but the left was working , today both are not working even with new bulbs.


Tried swapping bulb holders around with no luck.

I am worried it might be rear SAM , heard its expensive to replace and need coding, can they be repaired by likes if BBA reman?

 

[markjay]

Hi , replaced bulbs with new , still nothing , battery is 2 months old genuine and fully charged.

I have Icarsoft and it only says right brake bulb defective.

The problem started few days ago , got a message on the dash about Right brake bulb , but the left was working , today both are not working even with new bulbs.


Tried swapping bulb holders around with no luck.

I am worried it might be rear SAM , heard its expensive to replace and need coding, can they be repaired by likes if BBA reman?

Could it be an issue caused by water ingress into the rear SAM?

 

[amazighman]

Never seen water ingress, car is dry so is SAM area also

 

[whitenemesis]

Corroded lamp holders?
Do you have the correct type of brake lamp fitted?
What happens if you switch on the rear fog lamp and press the brake pedal?

 

[amazighman]

I haven't tried that , will have a go in the morning.
Problem is both brake lights are not working on both lamp holders , I am sure I have the correct type bulb.

The OBDII scan with Icarsoft only shows bulb fault

 

[wongl]

The bulbs are fine , there was a warning on dash Right brake light , but no warning anymore , however no brake lights.

How did you verify the 'bulbs are fine'?

Hi , replaced bulbs with new , still nothing , battery is 2 months old genuine and fully charged.

The bulbs may be new, have you actually verified that they are working?

I ask this because this actually happened to me a while back; I replaced both rear brake lights shortly before an MOT. The car then failed MOT due to the rear brake lights not working. I told the MOT tester that I only replaced the bulbs the day before the MOT. So poor guy went into full diagnostic mode, checking the fuses, wiring, and bulb holder until the MOT manager came out to tell him to release the car off the MOT ramp. As a final attempt, he replaced both bulbs with new bulbs from his stock, and low and behold the rear brake lights started working.

Unbelievable, but both bulbs I purchased from a well known high street chain failed almost immediately.

 

[amazighman]

I dont know if this is related , but the tail lights had the wrong bulbs in then , they normally take P21/4w but instead had P21/5W forced in as the bulb lugs are slightly different position.

Yesterday night everything was working fine strangely, and this morning I fitted the correct bulbs for tail lights

 

[Stratman]

Am I correct in recalling some bulbs commonly sold by a chain of well known high street bicycle shops didn't quite fit the holders correctly, throwing up all sorts of problems from no light to melting holders?

 

[amazighman]

Sadly the problem is back again.

This time , warning on dash , brake light left , substitute lights on .
The warning stopped showing , however no brake lights.
The middle brake light on tailgate works ,
I did fit new bulbs but no joy ,

Is it rear sam that controls the brake lights?

 

[amazighman]

Anyone?

 

[markjay]

The brake light bulbs on this car are funny. I think the bionet is different to standard, and also it's 21w/4w as opposed to the standard which is 21w/5w. This is all from memory, I had a W203 but sold it a few years ago. But I definitely remember that the brake light bulbs were an odd fitment. Worth double checking that you have the correct type of bulb.

 

[markjay]

I think the bulb you need is type 566, and not type 381, although they look very similar.

 

[amazighman]

I think the bulb you need is type 566, and not type 381, although they look very similar.

From the manual it states that fir rear brake lights the car takes P21W 382 bulb

 

[markjay]

From the manual it states that fir rear brake lights the car takes P21W 382 bulb

That's the main brake bulb, the dual-filament bulb is the backup brake bulb.

 

[amazighman]

On this car , the substitute brake/ tail lights at the very top of the cluster have a P21W bulb , so do the main brake lights.
The only ones with dual filament is the tailgate lights... This is what I saw on the car and in the owners manual.

 

[markjay]

On this car , the substitute brake/ tail lights at the very top of the cluster have a P21W bulb , so do the main brake lights.
The only ones with dual filament is the tailgate lights... This is what I saw on the car and in the owners manual.

Fair enough, mine was the saloon (not coupe), perhaps the rear lights cluster is different.