Auto lights inoperative?

[Kris9611]

Hi everyone,

hope your all safe and well

I bought a 2012 C200 and it now comes up with “auto lights inoperative” (they do work) this affects the entertainment system and radio sat nav can stay off by up to 10/15 mins at time? Has anyone seen this and is it just as simple as replacing the auto lights sensor

My first time using a forum so apologies if I’m this is in the wrong place.

 

[dry run]

Welcome and sorry I can't help

 

[Botus]

seems strange - so my deduction may seem a bit wild... this sounds as if the time and date might be interfering.... can you find the time and date settings and confirm if BOTH are 100% correct?

I'm pretty sure my car will swap the comand day night colours according to the time of year rather than exclusively using the amount of daylight out there. It might have an either or bit of logic buried in there - but I notice at certain times of year it swaps at the same time even if its still bright light

and the reason I mention is because if the lights are coming on and off but you still get an error, is it something is out of step and so its warning it may misbehave - if out of step why - maybe its april 2019 when lots of sat navs lost the ability to get the time and date right including BST

if you do find the data awry - it could be a software bug that needs plugging in to Germany to tell it how the world now works

alternately - check if this was standard equipment from the factory, or part baked / after market add-on ?

 

[EmilysDad]

I found there is a link between the auto lights & the wipers. A few months back, the weather was heavy drizzle so not especially light but by no means dark. The auto wipers were doing their thing & I noticed that the lights were on even though, as said it was day time but heavy drizzle. Just to try, I knocked the wipers off & immediately the lights switched off. Switching the wipers back to auto triggered the lights to come back on again soon after. I did the same thing a little later just make sure the first time wasn't a fluke, and again, switching wipers off also turned the lights off.
Up shot being ..... if the weather is bad enough for wipers, then the proper lights should be on.

 

[Blobcat]

I found there is a link between the auto lights & the wipers. A few months back, the weather was heavy drizzle so not especially light but by no means dark. The auto wipers were doing their thing & I noticed that the lights were on even though, as said it was day time but heavy drizzle. Just to try, I knocked the wipers off & immediately the lights switched off. Switching the wipers back to auto triggered the lights to come back on again soon after. I did the same thing a little later just make sure the first time wasn't a fluke, and again, switching wipers off also turned the lights off.
Up shot being ..... if the weather is bad enough for wipers, then the proper lights should be on.

It’s a requirement in the Highway code, if you wipers are on anything above intermittent then headlights need to be on. So if your auto wipers are sweeping constantly, the lights are switched on.

 

[Botus]

It’s a requirement in the Highway code, if you wipers are on anything above intermittent then headlights need to be on. So if your auto wipers are sweeping constantly, the lights are switched on.

not so sure anymore - it was and it should be
but last time I looked it changed to - if its daylight who cares....

@EmilysDad on quite a lot of cars the auto lights turn on under a certain level of low light and "may" then stay on to the next key on off cycle (and or a time frame of unknown duration). So you may have had then come on due to low light levels as it started to rain then brightened up

On my sister's 2014 Mk3 focus the auto lights have a well hidden user option to turn ON (or default leave off) the lights, if the rain sensor see's rain
On the Mk2 focus its off and always off unless really dark (which is stupid)
On my S class I think its like the Mk2

 

[EmilysDad]

.....

@EmilysDad on quite a lot of cars the auto lights turn on under a certain level of low light and "may" then stay on to the next key on off cycle (and or a time frame of unknown duration). So you may have had then come on due to low light levels as it started to rain then brightened up
....

Lights turned off just after I'd turned the wipers off .... and as above, they did exactly the same a little later ... definitely not a fluke

 

[Botus]

yep, its stops raining as the clouds clear and it brightens up - then both can stop for different reasons - doesn't have to mean they are connected.... (of course there is a connection in some behaviour as both driven by the same sensor on the front windscreen, but the logic is down to how the eng "bothered" to do the software)

simple check, pour a watering can on the screen in bright weather and see if the lights come on.....

 

[EmilysDad]

yep, its stops raining as the clouds clear and it brightens up - then both can stop for different reasons - doesn't have to mean they are connected.... (of course there is a connection in some behaviour as both driven by the same sensor on the front windscreen, but the logic is down to how the eng "bothered" to do the software)

simple check, pour a watering can on the screen in bright weather and see if the lights come on.....

there was obviously a connection, it would have been a double coincidence that the auto lights turned off within a few seconds of the wipers being turned off from auto