Esp/Bas C250turbo Diesel 1999 Estate

[David Massey]

I have just started having problems with the warning light coming on intermittently,and not every day.Any ideas?

 

[television]

Yes, full of idea's, it is the brake lamp switch on the brake pedal.
standard fault, cost£12 easy to fit.

Malcolm

 

[jberks]

incase you need a second opinion ... ditto.

 

[malcolm E53 AMG]

Ad me to the list too!

 

[David Massey]

Many thanks for your replies.It has illuminated even though i haven't touched the brakes is this the norm?

 

[television]

Many thanks for your replies.It has illuminated even though i haven't touched the brakes is this the norm?

That is the problem.

Malcolm

 

[jberks]

There is a vague possibility that it's something else, but the switch is both cheap to replace and notorious. You'll be hard pressed to find anyone who has run post '97 Mercs for a few years and not had that switch replaced! Assuming we are all wrong, you'll have wasted £15 (inc fitting). The alternative is a diagnostic which will set you back at least £60 which will likely tell you it's the switch, so its a good gamble.

 

[Dunx]

In general, I would agree but would like to add that a failing battery may also cause a BAS warning. Happened to me ('97 T210 E300TD) a few weeks ago. I had a few spurious BAS warnings when I started (usually on cold mornings). When I replaced the faulty battery (previous owner put a smaller battery in so they could fit a CD changer next to it under the rear seat - it obviously couldn't cope with cranking such a big engine and died.) I no longer experienced the BAS warnings. The voltage drop during cranking must have been too much for the BAS system.

Might be worth having the battery checked (usually motor factors will do this FOC). If the battery is fine, it's the brake light switch.

Duncan

 

[David Massey]

I have replaced the switch, and thought briiliant,no sign of the light but then hey presto its back again......any further ideas beforre I have to pay mercedes!

 

[jberks]

As I said above, it was worth the gamble. At this point you are into more expensive components. Could be the battery, could be a sensor. Whatever it is, the info is sitting in the ECU but you'll need someone to interrogate it. Ideally, bob it down to a specialist who will do it for 1/2 the price, but otherwise, yes I'd be visiting the dealer.