2004 Mercedes C200 W203 Electrical issue on startup

[sailski]

Hi all,

Hoping someone within this wealth of knowledge of a forum might be able to help me with my bizarre glitch!

I've got a 2004 W203 C200 Coupe CDI.

Seemingly worst when it's cold but sometimes, when I turn the key, the speedo, tacho, etc will start then when the car starts, they turn off. With this the stork stops working controlling the indicators / wipers as does the blower module. Usually if I turn off turn back on again it's all sorted. Intermittently the cruise control also stops working. Today however there was nothing for a few key turns, could hear a slightly high pitched noise in from under the bonnet then it started. By the time I'd got to work it was warm and no further issues... Very odd.

Anyone got any bright ideas as to what could be causing this!?

Really appreciate any help.

Cheers

 

[ruston]

At a wild guess with older Mercs the wiring harnesses suffer from corrosion and damage , The high pitched noise you heard may be a relay trying to latch .
If the problem is intermittent I have a feeling this is your problem.

 

[PEG]

Yes,it does sound like an individual circuit is being dumped. There are so many electrical issues,with models such as yours,i would be tempted to have a look on a model specific forum.
Other places,like BBA,have Q&A sections and lists of common problems,where fixes and re-worked components can be purchased.

It could very well be a relay,or the contacts,to it,or the tracks on it's power board,or the feed to that board,or.......

One of the most painstaking,futile and frustrating tasks,i ever had,was to rebuild a control/fuse board,off a Mercedes MIL 4WD. They have 7 layers of interconnected PCB's,in a sandwich,only using leaked rainwater,instead of butter...

I would rather play Scrabble,with Donald Trump,than do another one

 

[ruston]

I have repaired 3 ML harnesses recently under the inner front wing to the ABS unit. Multiple code faults associated with ABS / steering and other associated faults. The harness literally turns to brown powder and a replacement is a fortune.
The job is a nightmare ; like Peg - I would sooner watch paint dry.

 

[Wilko]

Hi - starting simple - my thought is to have your battery load tested. In my experience the older MB are very sensitive to voltage drops during cranking at start.

 

[PEG]

Hi - starting simple - my thought is to have your battery load tested. In my experience the older MB are very sensitive to voltage drops during cranking at start.

....Whilst the newer ones,are sensitive to being made shoddily,in South Africa,using child's toy quality electronics...

 

[ruston]

It's sad isn't it. Once renowned for quality , now usually destined to the scrappy for lack of it.
Ps , Range Rover are not much better.