CLK W209 - how to get rid of message

[beefbeefbeef]

I have message come up which says "replace left brake light" however the left brake light appears to be working fine. A quick look at the manual says the way to get rid of this message is to replace the bulb but I'd rather just reset the message!

Is there a way to do this? I couldn't immediately see it in the manual.

Cheers

 

[whitenemesis]

The message is there because the system has detected a fault. You need to address the cause. The bulb may well be ok but it could be an intermittent fault, poor connector?

You are aware that on detecting a faulty bulb the system will use a substitute?

 

[beefbeefbeef]

You are aware that on detecting a faulty bulb the system will use a substitute?

How does it use a substitute?

 

[whitenemesis]

It will use a tail lamp or rear fog lamp

 

[ItalianTuneUp]

How does it use a substitute?

Yes, I was surprised too when I got the dash message informing me that it was using a substitute.

My rear light cluster may differ from yours, I don't know, but in my car's case, the LED brake light had stopped working, and so it was using the standard looking bulb as the substitute iirc. Of course, MB don't sell the LED component separately, so I had to buy a whole new cluster.

 

[beefbeefbeef]

It will use a tail lamp or rear fog lamp

Interesting, thanks. In that case, I need to have a closer look and see whether it is using a substitute. Certainly when I brake there are lights on both sides.

 

[beefbeefbeef]

Yes, I was surprised too when I got the dash message informing me that it was using a substitute.

My rear light cluster may differ from yours, I don't know, but in my car's case, the LED brake light had stopped working, and so it was using the standard looking bulb as the substitute iirc. Of course, MB don't sell the LED component separately, so I had to buy a whole new cluster.

I've not got a dash message saying it is using a substitute, just that the left brake light is not working. I wonder if that means it is not using a substitute in my case.

 

[ItalianTuneUp]

I've not got a dash message saying it is using a substitute, just that the left brake light is not working. I wonder if that means it is not using a substitute in my case.

Ok then, and it sounds like it's using something as you say there are lights when braking on both sides.

 

[beefbeefbeef]

Either that or it is an intermittent problem - having said that the message is coming up every time I use the car since yesterday morning so it doesn't feel like it's intermittent.

I suppose I will be able to tell whether it is using a substitute by looking at which lights are illuminated. If it's a different light on each side then that will be the giveaway.

 

[Sp!ke]

a working bulb can also cause this message if it isnt the exact same resistance of the bulb it replaced.

 

[GP801]

The warning system measures resistance. It will have detected a bulb that is about to fail. Simplest just to replace the bulb

 

[beefbeefbeef]

That is a revelation - the system can give a message saying "replace bulb" even if the bulb has not (yet) failed?

That may explain why both of my brake lights are still working yet I still get the "replace bulb" message.

 

[mersum1es]

That is a revelation - the system can give a message saying "replace bulb" even if the bulb has not (yet) failed?

That may explain why both of my brake lights are still working yet I still get the "replace bulb" message.

Yes, vrey often corroded contacts will trigger fault, and of course wrong W bulbs or retrofit leds without correct resistance...

 

[LTD]

It might also be the bulb holder that is faulty - usually corrosion. Try swapping the bulb / holder from the other side.

Cheap part from the dealers.