W203 c270 starting issue

[Kristof1989]

Long story story short, had a running issues with the car which would cause the car to take a lot of cranking to start. Finally got it sorted and a few days later i noticed the battery was getting weaker and weaker. So i brought a new one. When i fitted one of the relays in the left hand engine bay area was buzzing like a bee then when i put the key in the ignition it would stop and the rad fan would come on and the car wouldnt start. I took the battery terminals off and left over night then reconnected in the morning. All was fine.

Went out to the car this morning and every time i put a key in and turned no glow plug light would come up and the fan would come on again. Id have to take the key in and out turning it on off a few times before the light would come on and it would crank to start. Thats one issue

The other issue i have is it randomly stopped working with two of the keys, they would work now the car does not recognise them so im down to my final key which im worried the same will happen and leave me without a key that works.

Any suggestions??

Thanks in advance

 

[estate-agent]

Not sure if this will help that much but when I had a problem with a flat battery on refitting a charged battery my key fobs appeared not to work, but if I held the key up close to the cars drivers side handle it would work. It needed a form of re-sync to recognise the keys properly again.

I think this is how I did mine (but don't quote me as I can't quite remember)

HELP please CLK 3.2 2004 reprogram key - Mercedes-Benz Owners' Forums


Sorry I cant help with the relay / fan issue but may well be related to key issue somehow?


.

 

[Kristof1989]

After a lot of searching online I came across a foreign video which showed something about a fuse which is in the fuse/relay box on the drivers side (rhs) bulk head area l. It basically showed the relay not working even though it was fine. It showed a way of temporary fix which was to force it to make a connection by wedging a bit of paper in it. This I only temp as I'm guessing the battery will go dead after a day or two.

So it's like the relay is not getting power or is not working as it should. I tried a new relay which still gave me the same issue. When the car used to start it would cut out while driving 2-3 miles up the road and refuse to start again and give me all sorts of warning lights come up.

When I put the paper wedge in the relay it starts first time every time and drives perfect. I want t solve the issue so has anyone got any ideas what the issue is?

Couple of pictures to show what I done go relay

Thanks guys

 

[estate-agent]

That's an odd one I reckon. I've not had my CLK very long so not too clued up on all the regular "faults" that seem to happen.

So it sounds like a lack of power to the relay. I think you need to try and get some wiring schematics so you can trace wires back and check for connection and continuity, but that no doubt will also be no easy task!

From fixing many many cars over the years I would (as others probably will say) check and double check earth points, undo earthed wires and clean up connection and spray with white grease before re-fitting. Something as simple as a bad earth can set all kinds of issues off in modern cars.

Sorry I can't be of more help, shame your not in Devon you could have brought it round and we could both check it over and try and shed some light on it.


.

 

[stevegi]

i had exactly the same problem but without the relay buzzing on turning the ignition key id have no glow light but the engine cooling fan would run full speed, to get it going i had to keep turning the key on and off some times as many as 50 times then eventually the glow light would come on and it would start, i took the car to an ex mercedes engineer who now runs his own work shop apparantly there is a printed circuit board somewhere that controls all of the front of the car this had to have the software replacing he had to send the board away to be done costing £550 pounds to be done this cured the problem straight away and hasnt been a problem since.