I have learnt more about windscreens in the last 5 days than I've had to in the last 22years of driving.

I have a C200SE W205 2017 model with 2400miles on it. Driving on a wet country road at 25mph through some muddy roadworks with a slight lane narrowing some idiot flashed by on the other side +40mph ignoring all the roadwork signs and conditions of the road. I was greeted with a sharp loud CRACK!. I had been the recipient of a stone chip.

Apparently it is a "combination chip" with circle mark and radiating stars. Even tho when I look through the screen the wiper area/bonnet is the only thing behind the chip it falls in the A zone and as it was 2cm length the Autoglass guy that I called out declined to fix it as he had no windscreen available to replace. Bit peeved as I had taken photos of the position with a ruler next to it and MMSd them to Autoglass as per their instruction.

Now for the real fun and games. The Autoglass guy says I think we need to do the replacement in the workshop as the sensors need calibrating. What sensors? Ah the stereo cameras that do the brake assist. We look and on the c200 se (base model) they appear to be blanked off. I confirmed they definitely were not present later by standing on the scuff plate of the drivers door and craning over the windscreen from above. I was surprised at the time he said it as I had just got the active brake assist working and the workshop guy said it needed a front bumper removal to do that.

So I researched ABS online. Apparently there is a difference between the active brake assist which I suspect just uses the radar tech in the front to the BAS Plus which uses the stereo cameras in the rearview mirror to detect crossing traffic and pedestrians also. It took me a while to figure out.

Talking to my local MB dealership servicing they were a fat lot of good. No knowledge whatever. So I try to contact Mercedes Me Connect. No connection/reply so far... Obviously I ring Autoglass as well. also not that helpful oh yeah they can calibrate that for you on site... yeah Im thinking is that why your tech said to bring it to a workshop...?

So I tried Merc Connect from my car. A but more helpful. 2 receptionists initially with no knowledge at all. I get put through to a 3rd female receptionist in what appears to be a Milton Keynes dealership. She 'kind of' confirms the stereo cameras are not fitted for my c200 but doing a bit of upselling I suspect says there is a rain and light sensor part that could require calibration instead. They could do it in MK for 90gbp. Urrmm not that useful to me I say as I'm in Hertford...

I now understand through more internet research that the rain and light sensor are integrated into the same part. It is located under the windscreen facing up on on the rearview mirror module.

I know I can get the part separately to fit. Although I have read some confusing reports that the sensor may come attached to the windscreen. If anyone can tell me whether it does come attached to an MB or aftermarket windscreen that would be good???

I am going to do some more digging but I reckon the windscreen can be removed with disturbing the rain/light sensor too much. I'm just going to go for it.

If it happens to need calibration I strongly suspect that I can take it into a garage and they can open up the plastic sensor cover from inside. But I will do a bit more digging today and let you know how I get on with the windscreen replace tomorrow...

 

More knowledge for the forum...
Okay the rain / light sensor is attached to the windscreen.
I just got a Pilkington one fitted as there's no way I'm going to pay £280 extra to Autoglass for them to order a windscreen with a "Carl Benz" signature and a little Mercedes symbol.
It did have the DAB aerial filament fitted also. No calibration required which makes sense really if the sensor is already attached to the windscreen. I put a dribble of water on the windscreen over the new sensor and it responded with the wipers promptly moving. I also shaded the sensor with a cupped hand and the lights came on and then turned off okay.
Another unexpected thing is both fine strand wires for the windscreen aerial connection had been cut at the factory [blanked off] and potted with some kind of sealant so there was no electrical connection to the aerial elements in the C200 SE that we could note. So even though the Pilkington one had a small rectangular connector on each side of the windscreen nr the aerial the fitter would not have been able to connect it.

So the only DAB / Tel / radio aerial is via the back windscreen aerial. So that was another learning point for me.

No calibration needed on the C200 SE for any brake sensor for the windscreen replace and as I said above no stereo camera fitted.

Hope this helps. Although be careful as for other C Class models. Check for the stereo cameras (it will be fairly obvious and there are photos on the internet to help you) and don't let MB get you to pay for a windscreen with a signature or unnecessary calibrations as I could have been a further £360 down as well as the £90 excess I've had to pay.

 

Doesn't your car insurance cover the replacement?

 

Insurance will cover a non MB windscreen and may cover certain calibration "on site". But for some calibration of front facing cameras they require the car to be taken to a workshop. So obviously thats a cost to you in terms of petrol cost/ your lost time / time off work / alt transport etc.

As I said Autoglass will require you to pay a further 280gbp to finance the cost of a Mercedes windscreen. Lord only knows what the base cost is to Autoglass ... not cheap I guess.

Dealership would love to charge you £80 odd to calibrate just the rain sensor... even if you dont need it! So yes. Try and make sure the windscreen repairer does it.

I guess you could claim off insurance if the cost becomes additional to the standard windscreen excess cost.