Odd electrical problem. Mercedes-Benz 2003 C200 Kompressor W203

[AzmiQ]

Hi all,
I have a C200K (W203) 2003 model which recently started to act up.

The problem started with the automatic windscreen wipers not working. I have to keep holding the stick to get them to work. Sometimes, when I signal left, the automatic wipers work.

Then the instrument dashboard light started dimming after time. When I first start the car, it's ok and bright. But then it starts to dim the more I drive until it is no longer readable.

Then the driver-side automatic window started to "lose power" as well. When I first start the car, everything is fine. But after I drive a bit, it stops rolling back up.

Today, I started the car and the whole dashboard wasn't working. No warning signs. No lights. Even the speedometer and the petrol meter didn't move.
After removing & inserting the key multiple times, they worked again, but now the SRS restraint system control worning is on.

I checked all the fuses and couldn't find any fault in any of them. I had the window switch checked, and there doesn't seem to be a problem in it.

I'm not sure where the problem is, whether it's a faulty SAM or a battery issue or what exactly.
I took it to a garage and they couldn't figure out what's wrong with it. I'm due to take it to another garage soon, but I'd like to have a general idea what to look for so that we don't miss anything this time.

Apologies for the long post.
Thanks!

 

[Wighty]

Hi all,
I have a C200K (W203) 2003 model which recently started to act up.

The problem started with the automatic windscreen wipers not working. I have to keep holding the stick to get them to work. Sometimes, when I signal left, the automatic wipers work.

Then the instrument dashboard light started dimming after time. When I first start the car, it's ok and bright. But then it starts to dim the more I drive until it is no longer readable.

Then the driver-side automatic window started to "lose power" as well. When I first start the car, everything is fine. But after I drive a bit, it stops rolling back up.

Today, I started the car and the whole dashboard wasn't working. No warning signs. No lights. Even the speedometer and the petrol meter didn't move.
After removing & inserting the key multiple times, they worked again, but now the SRS restraint system control worning is on.

I checked all the fuses and couldn't find any fault in any of them. I had the window switch checked, and there doesn't seem to be a problem in it.

I'm not sure where the problem is, whether it's a faulty SAM or a battery issue or what exactly.
I took it to a garage and they couldn't figure out what's wrong with it. I'm due to take it to another garage soon, but I'd like to have a general idea what to look for so that we don't miss anything this time.

Apologies for the long post.
Thanks!

Just a thought if this car has cam magnets on the top front of the engine . They can leak oil and this works its way into the wiring that goes to the front Sam .
A quick check of unplugging the electrical plugs to the two front cam magnets to look for oil will show if further investigation into the front Sam (for oil) is worth doing .
The two round things are the cam magnets

 

[AzmiQ]

Just a thought if this car has cam magnets on the top front of the engine . They can leak oil and this works its way into the wiring that goes to the front Sam .
A quick check of unplugging the electrical plugs to the two front cam magnets to look for oil will show if further investigation into the front Sam (for oil) is worth doing .
The two round things are the cam magnets
View attachment 88759

Apologies for the late reply!
Thanks for your help.

My car doesn't have cam magnets. But I managed to find the issue. It was the rear sam, which has a blown fuse that's melted onto the sam. It will need to be replaced unfortunately.
I talked to a garage and they said it would cost me £300 for the new sam + programming it, which is awfully expensive!

I'm looking into getting a second-hand sam. As far as I'm aware, if the correct part is selected, it should be relatively "plug & play". But if it comes to it, can it be re-coded? I assume it can, but the garage has me worried and said that they don't deal with second-hand parts and don't know if they can be re-coded.

 

[Uncle Benz]

They can be recoded by any decent independent specialist with a Star machine

 

[AzmiQ]

Quick update
I had the rear SAM changed and the problem wasn't solved. The SAM had a burnt fuse, so I assumed fixing it would fix the problem, but it didn't. I had the garage run a diagnostic and they couldn't figure out what the problem might be besides the SAM.
At the moment, the electrical problems got worse. The dashboard is faulty and doesn't turn on. Even the fuel cap isn't opening now, as it is locked & unlocked electronically. So currently, I can't know how much fuel is in the car (the dashboard doesn't work) nor even fill it.
I haven't got a "licenced" Mercedes repair shop near where I live, and in it's current state, I don't think it would be wise to drive the car far for "official" repairs.

What would be a good next step?

 

[SL63 Mark]

Tell us where you live and we can recommend a decent Mercedes independent specialist.

 

[peterws1957]

Quick update
I had the rear SAM changed and the problem wasn't solved. The SAM had a burnt fuse, so I assumed fixing it would fix the problem, but it didn't. I had the garage run a diagnostic and they couldn't figure out what the problem might be besides the SAM.
At the moment, the electrical problems got worse. The dashboard is faulty and doesn't turn on. Even the fuel cap isn't opening now, as it is locked & unlocked electronically. So currently, I can't know how much fuel is in the car (the dashboard doesn't work) nor even fill it.
I haven't got a "licenced" Mercedes repair shop near where I live, and in it's current state, I don't think it would be wise to drive the car far for "official" repairs.

What would be a good next step?

I take it you've checked the battery voltage and output from the alternator? MB's throw total wobblers with battery/alternator problems.

 

[AzmiQ]

Tell us where you live and we can recommend a decent Mercedes independent specialist.

Thank you. I live near Newquay in Cornwall. The closest Mercedes dealer according to google is in Truro, which takes about 30 minutes by car. The problem is that they haven't got any recent appointments, but I'll try and see if I can get an urgent appointment for "emergency" repairs.

I take it you've checked the battery voltage and output from the alternator? MB's throw total wobblers with battery/alternator problems.

Yes I checked the battery and nothing seems to be wrong with it. I'm not sure where else the problem is.

 

[peterws1957]

Thank you. I live near Newquay in Cornwall. The closest Mercedes dealer according to google is in Truro, which takes about 30 minutes by car. The problem is that they haven't got any recent appointments, but I'll try and see if I can get an urgent appointment for "emergency" repairs.


Yes I checked the battery and nothing seems to be wrong with it. I'm not sure where else the problem is.

I really would not be taking a 2003 car to a Mercedes dealer unless you are prepared to be hit with a large bill (read very large). Are there no MB independent garages near you?

 

[Larkone]

Independents in Cornwall - no connection, just a google search

Merc AutoCare – an independent Mercedes and Smart car specialist – Cornwall's Largest Independent Mercedes Specialists

www.autocarecornwall.co.uk

Welcome to Cornwall's Independent Mercedes Specialist | Truro

Truro Motor Services specialise in the service and repair of Mercedes-Benz passenger cars, smart cars and light commercials.Established 2002

truroms.co.uk

 

[AzmiQ]

Independents in Cornwall - no connection, just a google search

Merc AutoCare – an independent Mercedes and Smart car specialist – Cornwall's Largest Independent Mercedes Specialists

www.autocarecornwall.co.uk

Welcome to Cornwall's Independent Mercedes Specialist | Truro

Truro Motor Services specialise in the service and repair of Mercedes-Benz passenger cars, smart cars and light commercials.Established 2002

truroms.co.uk

Thank you. I called them before and they can only see the car after a month.

I really would not be taking a 2003 car to a Mercedes dealer unless you are prepared to be hit with a large bill (read very large). Are there no MB independent garages near you?

I took it for a diagnostic just to know what I'm dealing with, with the idea that at least they'll tell me the problem quickly and I'll look for an independent garage to fix it. Sadly, they didn't have a clear idea what the problem was and said that the next step would be to start replacing parts and see what fixes the problem, which is obviously expensive.
Looks like I'll be in the market for a new car sometime soon.

 

[peterws1957]

Thank you. I called them before and they can only see the car after a month.


I took it for a diagnostic just to know what I'm dealing with, with the idea that at least they'll tell me the problem quickly and I'll look for an independent garage to fix it. Sadly, they didn't have a clear idea what the problem was and said that the next step would be to start replacing parts and see what fixes the problem, which is obviously expensive.
Looks like I'll be in the market for a new car sometime soon.

"Start replacing parts etc" - sounds like a wallet emptying approach to fixing the problem, and you'll still be hit with the bill for parts even if the parts darts doesn't fix it. Awkward position to be in - not sure what I would do.