W204 - Windscreen Wipers intermittently totally unfunctional, Stutter Starting & Squeaking Blower

[Orta]

Hi All,

Had my C250 CDI for just under a year. I bought it from Specialist Mercland, in Nuneaton, February 2020, and whilst it's an absolute pleasure to drive on my 33 miles-each-way commute 99% on the A1 and I'm getting decent enough mpg (42 average by Spritmonitor.de records) it's been fairly pants in the reliability department. It was my first privately bought car in 5 years after opting out of my company car scheme, I wanted to buy a cheaper older car outright with the view of then trousering the saved tax money for a couple of years to pay for some travelling we intend to do (If the govt ever lets us out of our houses again)

The car's never actually stranded me anywhere but there's been a couple of issues with it. One of my new year's resolutions is to get them sorted as 1). Either I'm keeping it for the second year and I don't want these to be issues ongoing or 2). I'm going to sell up, but don't feel right about moving a car with outstanding issues (I'm into Kharma).

Anyway, that's what brings me here. I wouldn't really call it an "enthusiast's car", although I am a car enthusiast I'm more into my VW Transporter these days, so am no stranger to car forums; but new to this one!

Got three issues that I'm wonder if you chaps would be able to shed a bit of light on for me please?

1). The Wipers...
So a week prior to that day we all randomly got snow a few weeks back the wipers would occasionally be unresponsive to my stalk commands. This always immediately fixed itself and tbh never thought anything more of it.

Then the day we randomly got all that snow the bloody things really went into overdrive. They'd basically be working for maybe 10-15 minutes, then stop working completely for another 10 minutes. This is terrifying, as you'd imagine, on the A1 raining heavy, spray from lorries etc. and your wipers just stop... I pulled over as soon as I could (This was a challenge) and fiddled with the stalk for a bit. Eventually they'd start working again, I'd drive off and they'd stop again.

I eventually got to work (My normal 40 minute commute taking about 1.5 hours!) and had to rush straight into the Office as I was already behind. Went back out to them at dinner and, of course, they functioning well. I sat in the car for an hour with the wipers just working.

Went to drive home, repeat performance of the morning.

Did some research online and didn't get a great deal back from googling. I'd hit a badger two days before lockdown back in March and it has messed up the front grill somewhat. I eventually had to replace the bonnet and the plastic grill (Everything else was fine), was a fairly low speed impact but you know how big those bastards are. Anyway I read somewhere it could be something to do with a sensor in the bonnet, which made sense as I'd replaced it myself.

Only thing that didn't ring try with this as a culprit was that when the wipers themselves weren't working the jets still would, which with the bonnet "released" they didn't.

Anyway, I lift the bonnet, WD40'd the catches (Where I presume the sensors are, the sites I visited kept mentioning these sensors but never told me where they were). Closed the bonnet again and the wipers seemed to be working!

I forgot about the problem and carried on with life. Then they totally failed on the wife two weeks ago. Fortunately it wasn't raining, she was just clearing the windscreen of some mud. She drove home with them stuck half way across the window.

I tried all the same tricks as before and nothing. Booked it in with my location independent (There's nothing on this Earth that would take me to a M£rc£d£s main dealer, and there's no local specialists), and of course they opened and closed the bonnet and they started working again. They did however get their computer to generate the error in the attached.

The wipers are now working but I'm terrified they're going to fail again mid-drive on some freezing cold and wet day. Anyone dealt with something similar? Or any advice?

 

[Orta]

2). Stutter Starting

Now this has been an issue since about 2 weeks after buying the car. I should've gone back to the dealer, but I was busy at work, then I hit that badger and figured they'd just say anything wrong was new and because of the accident. Then after I got it repaired we were all being told leaving our house with cause instant death so again I didn't go back to the dealer. And then... well it was too late.

Now it's never stranded me anyway, but it's incredibly embarrassing that everytime I go to straight my car (With the neighbours listening or my work colleagues, who are still driving their company audis, hear my turning it over and over and over and over).

So basically you turn the key and it's struggles, then kicks into life. Sometimes it'll fail and I have to turn again. Everytime I have to pump the crap out of the throttle, or you get nothing. It happens when the engine is cold, hot, has been on for 5 hours, stop for fuel, go to start it and it'll do it again, or whether it's been sat not moving for two weeks.

Then more recently you turn the key, and none of the ignition lights come up. This has done this odd occasions over the last year, but the other morning we jumped in the car to go shopping, and I turned the key 20+ times before the ignition lights finally came up.

I've just changed the key fob battery and it hasn't done the ignition lights thing again, and... very strangely, the stuttering starting seems to actually be a little better. It started at the turn of the key now 2/4 times, instead of 0/200 times.

I've had this in at my local garage, who couldn't diagnose the issue. I took it to a Diesel Specialist, who couldn't diagnose. Then took it to a German Diesel Specialist, who can't diagnose. There's nothing wrong with the usual suspects I'm told, starter motor, battery, injectors, fuel pump etc.

Anyone had this issue before? Know of a fix? Know a place that could at least identify the issue?

 

[Orta]

3). The squeaky Blower

Squeaks and interior rattles are my biggest bug bare when it comes to cars. I've literally sold up in the past to offload a car with a rattle I couldn't cure (Never buy a MK1 Auris!). So when buying the Mercedes one of the things I loved was that it was completely silent over most road surfaces.

Then a few months in there was an occasional squeak from the glove compartment area, tried in vain to identify and never did. It seemed to cure itself. Then after the car has been stood for a month (Working from Home) it now has this piercing squeaking noise from the fan blower (Which is the same noise as the original) on pretty much any speed (Seems quieter at higher speeds but this might be because it's being drowned out by the fan noise).

I've googled this and it seems to the fan needs "oiling", but I've read conflicting reports on where this is located? Some say it's under the bonnet at the back on the left. Others are saying it under the glove compartment? (For which I've found a handy access guide). Can anyone confirm which is correct before I have a go? Or know if there might be a different problem?

 

[Orta]

Thanks for taking the time to read guys (Sad I know doing this on Xmas day, but work has been nuts and haven't had a chance to stop and sit and write my whole war and peace AND get the image uploaded etc. You'll make my Christmas if I can fix these issues!

 

[Flyinspanner]

See if you can access the fan from the cabin filter LHS of the engine bay, squirt the fan shaft with wd40 or silicone spray.

your wipers - check the bonnet switch, there is an interlock that stops wipers operating when bonnet is open. If the switch is bad/loose/poor connection, then it may think bonnet open and wipers stop....

 

[Orta]

See if you can access the fan from the cabin filter LHS of the engine bay, squirt the fan shaft with wd40 or silicone spray.

your wipers - check the bonnet switch, there is an interlock that stops wipers operating when bonnet is open. If the switch is bad/loose/poor connection, then it may think bonnet open and wipers stop....

Hi mate thanks for coming back to me.
Whereabouts is this bonnet switch?

 

[190]

The wipers are now working but I'm terrified they're going to fail again mid-drive on some freezing cold and wet day. Anyone dealt with something similar? Or any advice?

I don't know if this is the cause of your problem but I had a similar issue with the bonnet switch playing up and giving me a bonnet open warning on the dash. A micro switch is integrated with the offside bonnet latch only so sometime a firm push on that side of the bonnet would fix it otherwise I had to open the bonnet and close it again. This fault only ever happened to me after I had the bonnet open and never intermittently when under way.

It was obvious from the symptoms that the micro switch was only barely being actuated so I removed the black plastic cover on that side and looked at the latch and switch to figure out how it worked. From memory it's just an ordinary microswitch with a spring metal arm actuated by the latch. I bent the metal arm a little to ensure that when the latch was closed it more than barely operated the micro switch and that solved the problem.

An MB dealer would of course not have looked to see how it worked, they would simply replace everything in sight as I doubt the switch is available separately from the latch.

 

[jsnmac]

3). The squeaky Blower

Squeaks and interior rattles are my biggest bug bare when it comes to cars. I've literally sold up in the past to offload a car with a rattle I couldn't cure (Never buy a MK1 Auris!). So when buying the Mercedes one of the things I loved was that it was completely silent over most road surfaces.

Then a few months in there was an occasional squeak from the glove compartment area, tried in vain to identify and never did. It seemed to cure itself. Then after the car has been stood for a month (Working from Home) it now has this piercing squeaking noise from the fan blower (Which is the same noise as the original) on pretty much any speed (Seems quieter at higher speeds but this might be because it's being drowned out by the fan noise).

I've googled this and it seems to the fan needs "oiling", but I've read conflicting reports on where this is located? Some say it's under the bonnet at the back on the left. Others are saying it under the glove compartment? (For which I've found a handy access guide). Can anyone confirm which is correct before I have a go? Or know if there might be a different problem?

Fan unit needs replacing I would say. I have had this on my last C class. Sounded like a squeak or a bird chirping when cornering. If this is the case then lubricating it will make no difference as the bushes and bearings are worn. It is very annoying and the replacement of the fan unit is very easy to do.

 

[MrGreedy]

Hi and welcome. For all of these, I would always recommend (assuming failure to get accurate codes on first attempt with a generic scanner) that you should go to a Merc Specialist with STAR for the scanning of codes. It will give move detailed information and might be able to get codes from some of the other modules that generic scanners cannot.

Another member on here had an intermittent fault on something completely unrated, but they pulled at check all the relays in the SAM, and found one with slightly corroded terminals. Replacement cured their problem. Possibly a long shot, but free for you to check, and inexpensive to replace any if there is a sign of corrosion.

 

[Orta]

Hi All,

Thanks for coming back to me I hadn't realised anyone had replied and I never got an email despite being subscribed to this thread.

Hi and welcome. For all of these, I would always recommend (assuming failure to get accurate codes on first attempt with a generic scanner) that you should go to a Merc Specialist with STAR for the scanning of codes. It will give move detailed information and might be able to get codes from some of the other modules that generic scanners cannot.

Another member on here had an intermittent fault on something completely unrated, but they pulled at check all the relays in the SAM, and found one with slightly corroded terminals. Replacement cured their problem. Possibly a long shot, but free for you to check, and inexpensive to replace any if there is a sign of corrosion.

Would be happy to do this but unsure where my nearest Specialist would be. Can anyone give me any comments on these that flag up with a little google searching:
Click Here

I don't know if this is the cause of your problem but I had a similar issue with the bonnet switch playing up and giving me a bonnet open warning on the dash. A micro switch is integrated with the offside bonnet latch only so sometime a firm push on that side of the bonnet would fix it otherwise I had to open the bonnet and close it again. This fault only ever happened to me after I had the bonnet open and never intermittently when under way.

It was obvious from the symptoms that the micro switch was only barely being actuated so I removed the black plastic cover on that side and looked at the latch and switch to figure out how it worked. From memory it's just an ordinary microswitch with a spring metal arm actuated by the latch. I bent the metal arm a little to ensure that when the latch was closed it more than barely operated the micro switch and that solved the problem.

An MB dealer would of course not have looked to see how it worked, they would simply replace everything in sight as I doubt the switch is available separately from the latch.

Hi. I don't get a bonnet open warning on the dash. I've not had much luck looking for this "micro switch". I open the bonnet and I see the catches that the bonnet's U shaped bits close into.

I've WD40'd in there but I don't see anything I can bend? other than the catch itself?

Fan unit needs replacing I would say. I have had this on my last C class. Sounded like a squeak or a bird chirping when cornering. If this is the case then lubricating it will make no difference as the bushes and bearings are worn. It is very annoying and the replacement of the fan unit is very easy to do.

Replacements aren't super expensive so if that's the case no biggie. I've just had a go at removing the old one to see if it can be repaired but stuck at the last hurdle.

I've followed the removal video on Youtube from Pelican Parts Mercedes-Benz W204 C-Class Blower Motor Replacement DIY (2008-2014) - YouTube
Granted it's American but everything looks the same.

The part I'm stuck at is the last part where it says lift the tab and twist it out. 1. It's virtually impossible to lift this tab due to it's location but 2. even when I do manage to shoehorn it up the damn thing isn't moving.

I found another video where it said there was a screw to remove which the Pelican video doesn't, but where the other video shows the screw there isn't one in mine so that isn't the cause.

Anyone done this removal and have a better how to guide or at least some tips?

 

[MrGreedy]

In terms of local specialist, my recommendation that's not too far would be MB Automotive in Loughborough. I've had decent service from them and they were competitively priced.

I can't recommend Mercserve. I've used them twice and been disappointed both times, with the service received and the prices.

 

[jsnmac]

Hi All,

Thanks for coming back to me I hadn't realised anyone had replied and I never got an email despite being subscribed to this thread.



Would be happy to do this but unsure where my nearest Specialist would be. Can anyone give me any comments on these that flag up with a little google searching:
Click Here



Hi. I don't get a bonnet open warning on the dash. I've not had much luck looking for this "micro switch". I open the bonnet and I see the catches that the bonnet's U shaped bits close into.

I've WD40'd in there but I don't see anything I can bend? other than the catch itself?



Replacements aren't super expensive so if that's the case no biggie. I've just had a go at removing the old one to see if it can be repaired but stuck at the last hurdle.

I've followed the removal video on Youtube from Pelican Parts Mercedes-Benz W204 C-Class Blower Motor Replacement DIY (2008-2014) - YouTube
Granted it's American but everything looks the same.

The part I'm stuck at is the last part where it says lift the tab and twist it out. 1. It's virtually impossible to lift this tab due to it's location but 2. even when I do manage to shoehorn it up the damn thing isn't moving.

I found another video where it said there was a screw to remove which the Pelican video doesn't, but where the other video shows the screw there isn't one in mine so that isn't the cause.

Anyone done this removal and have a better how to guide or at least some tips?

There was one retaining screw on my C Class and, as the fan blower had been in there for 11 years at the time, was a bugger to lift the tab and twist out. I tried the lubricating route and found that did nothing for mine. Removing it for replacement was much easier the second time was much easier than the first.

 

[Tonygw]

The Blower motor is very difficult to get out, I did mine and it took me three goes at it. You lift the tab and twist but it catches on something not visible. I had to get my head right under the dash to get to see what it was stuck on, keep trying it will definitely come out. But takes determination. I didn't replace mine I squirted a lot of spray grease onto the bottom and top bearings Don't use WD40 it will need doing again in a few weeks.

As for the wipers it suggests its the bonnet switch, it wont always display bonnet open but it will stop the wipers from working. I had this when my bonnet was clsed but for some reason hadnt activated the bonnet switch, I think there are two of them. I give the bonnet a good slam these days and it seems to be fine.

As for the starting issue, have you checked the battery voltage? I found out that these mercs are VERY sensitive to battery voltage, My stop start, brake hold functions stopped due to a poor battery. Replaced and its like a new car starting, just a thought.

Other thought is, when was the fuel filter last changed? This will also cause problems starting. Its an easy DIY job but if its a none genuine or partially clogged fuel filter it would cause issues. They are not cheap on these, I think about £60 which is a lot for a filter, but is a service item.

Worth a shot.

 

[190]

You won't see the bonnet closed switch just by looking at the catch from above. The surrounding black plastic cover has to come off before you can see anything of the switch and then there is some dismantling involved. What you will see easily with the cover still in place is the wiring which goes to the switch and if as in my case, it is only present on the offside catch.

https://forums.mbclub.co.uk/attachments/image-1-jpeg.106771/