AUTO lights Inoperative
 

Can anyone help please.

I have got a 08 C220 and i have just been starting to get an 'Auto lights inoperative' display on my screen everytime i use the car. This makes my lights work only as side lights, even if i try and use the manual settings, and has also stopped all use of my window wipers! The garage i use who is an independent mercedes specialist tried to replace my light/wiper sensor at the front of the windowscreen but this has not solved it. He is currently testing out wires etc but cant find anything at fault. He seems lost at the minute and seems to think it will have to go to Mercedes. My worry is that mercedes advised on changing the sensor so they dont seem to know either. My garage has worked on these cars for ever and a day but hasnt encountered this before.

Has anyone ever had anything like this before?

Thanks

The difference is that your MB dealer has the correct MB diagnostic equipment to connect to the car and diagnose whats faulty. Their previous opinion was given without having done that so you should not take that as an indication of their "quality". Its always worth knowing whats wrong from someone who is fully trained on the vehicle. Just my view based on 5 years of work from my dealer from when the car was delivered new.

My mechanic learnt his trade for merecedes and spent a number of years working for them. He also has diagnostics and this along with speaking to mercedes was why they decided to change that part. I was simply asking for advice seing as ive already had to pay out for one wrong part, dont want it to happen again.

These sorts of problems are more easily diagnosed with a Star. If the light sensor is OK it could be anything from the light switch module to problems with a SAM or a CANBus short.

Thanks for the reply.
Would they also stop my wipers from working? If so are these big jobs?

It's unlikely that they are related unless it's a SAM issue or the fault lies in the overhead console.

Make sure fuses 10 & 13 in the front SAM are OK for wipers.

They are not big jobs if you know where the fault lies.

Possible overhead control panel fault, seen this happen before

Fuses have been checked, theyre all ok.

Overhead control panel? this sounds painful?! My wipers and lights have both gone at the same time so surely whatever it is has caused both to go.

Your guy needs to interrogate the data with a Star or Snap-on Solus or similar. If it's throwing a message it's storing a code.

Thanks,

He did say he'd checked it out with diagnostics and that was why he changed the sensor to start with.

What is the fault code via mercedes star machine, if communication fault with sensor then suspect will be overhead control unit

It might also be worth mentioning that i had my car in the garage last week and while it was in he altered the settings on the drivers window as the one touch setting had stopped working. That is now working but the other two fault (no wipers or lights) happened 2 days later. This wouldnt have made any difference surely?

He hasnt given me a code as yet. He says he has hooked it up to a diagnostics machine but will this be different to a MB Star machine?
I didnt realise the overhead control unit also ran my lights/wipers!!
Are these expensive to replace and would this show up on a star?

The wires for the light/rain sensor go into the overhead control panel and then onto the SAM unit. If you get a fault code it will help determine the problem, and with star machine you can go into fault code and it will tell you what to check and what unit is at fault.
If you have changed the sensor you will also need it to be coded for the right windscreen and adaptation carried out.

Thanks for your help, i will wait and see how he has got on once he rings, looks like it will be booked into mercedes, hopefully they will find it out for me, just a pain not knowing what it is!

Hope you didn't take offence at my contribution. I was merely trying to point out that with the incredible complexity of modern vehicles (and I worked with major auto OEMs for many years as a supplier), there is really only one way to find out whats wrong - use the manufacturer's own diagnostic equipment i.e. STAR.

The average specialist independent garage may be very good but they don't have access to this, nor the continual update training that their technicians get on new model innovations and adaptations.

My advice is that a quick dealer diagnostic check will not cost much in labour time but will probably give you all the answers you need and save you a lot of unnecessary parts costs. Then get your favourite garage to do the work. BTW I haven't experienced the issue you have although mine have been set to auto since the day I got it new. Good luck!

One point. The overhead console can get expensive. It does many things including the HVAC temperature sniffer.

Any really competent MODERN auto electrical guy capable of repairing modules can fix it. We have a good chap in Cape Town that repairs them at a fraction of the OE cost & you end up with a unit that is more reliable in the process.
You might want to seek out such a person.

Many thanks for your help!

I now have my car back, its working!! He says he's not sure why, he says he's taken out the SAM and then put it back in. I said surely it was the wires loose somewhere then but he wasnt so sure. The faults have also gone off the diagnostics now. Says if it goes again to take it to the dealers.
Im hoping its fixed but got a feeling this fault will soon be back!

Might have been a poor CANBus connection on the front SAM.

Screen Error "Auto lights inoperative" now wipers don't work at all.
 

A couple of months ago I got this error message. The radio elumination dimmed to night mode or went to day mode at night randomly. Later on the wipers / auto wipe went off intermittently and other times wouldn't work.

About 6 weeks or so later I had the screen changed as it was cracked. This didn't seem to make a difference but in the process of dealing with the fault I was advised by an MB specialist to check the switch on the left front boot catch. A bit of a clean fixed the problem for a short while now it's back and the wipers won't work at all.

Last week (another month or 6 weeks on) Star diagnostics at the local MB dealership confirmed 12v power to the wipers and controls, multi switch was ok but a number of errors were coming from the rain sensor and advised replacing the rain sensor.

My local MB specialist has changed the rain sensor but says this hasn't fixed the problem and wants to change the front SAM unit (very expensive) as diags say, amongst other things, the bonnet is open which it isn't and there were communications problems with the SAM. A call to MB who did the original diagnostics says the sensor needs recoding by MB, my specialist assures me his equipment can do this but he's taken the car to MB to run more diagnostics anyway.

Other posts on this site suggest overhead wiring or CANbus connection to front SAM unit could be the culprit. I've checked all the fuses are ok and have been reseated.

Can anyone throw any light on this please?

Auto Lights Inoperative
 

Hi, I've been reading this thread with interest as I have a vehicle that displays the same 'Auto Lights Inoperative' message. Our vehicle is a 2009/59 registration W203 CLC 180K Auto with Panoramic roof.

The vehicle has been into a Mercedes specialist (dealer trained and dealer level diagnostics) as well as an Auto Electric specialist locally that have similar level diagnostic equipment and massive experience with modern auto electrics.

So far the vehicle has had:
4 rain/light sensors,
a re-wired loom from OCP to light sensor,
replacement loom,
4 different OCP units,
2 replacement front SAMs and
a replacement switch unit (dash control).

All parts have been tested and are known to be the correct, working and correctly coded parts and none have resolved our problem. This has really got some people scratching their heads including MB technical support in Germany.

The fault code continually says there is an open circuit in the Rain/Light Sensor. Any thoughts or suggestions would be gratefully recieved but we're running out of ideas.

Are there any other vehicle functions that are involved in the cars decision as to whether the auto lights should operate?

I'm having this problem right now .. wiper is not working on my 2009 C300,
did he removed the front SAM ?

Auto lights i
 

My wiper is work water pump is working..
only when switch into Auto headlight mode.. it turn on all the time.. before that was left head light hid ballast faulty after replace a new original parts. Headlight is work but the auto light mode keep turning on day time..
and dash auto lights inoperative still on..
help needed as well here..
thanks guys..

-Merz Andrew

Auto lights i
 

Head light switch change as well.. incase somebody wondered

Gonna hit this old thread up. my 13 c250 is starting to throw the auto lights Inoperative. But at the same time the wipers do not work at all. But the auto lights are actually working. Its been to mercedes dealership 3 times and after 2200 in them just throwing parts at it as well as trying to find a short. I'm pulling my hair out because this was supposed to be covered under warranty and they are not doing so. The big thing is, it works one minute then stops the next. I would love to say its the wiring but this all happens from sitting in the same spot without hitting bumps or what not. I am picking up a new battery tomorrow as this is still the factory battery. I have read on some post that, a battery going bad can cause these problems. The starter is dragging a bit and Mercedes told me to replace it anyways. Also they star service is not showing any codes. That's the odd part. Any help would be appreciated.