W203 Headlight Sensor

[golfman]

Could anyone please give me some advice on the following. The auto sensing headlights on my W203 220CDI are now turning themselves on in bright day light, this can't be overridden by manually switching off the headlights. I'm not sure if it's the screen sensor, switch or other electronic gremlin, any suggestions most welcome.

 

[panason1c]

The auto headlight feature should definately be able to be overridden by switching to 'off' from 'auto' position (as is the case with mine).

I suspect the column 'lights switch' to be faulty due to an internal 'short' causing the lights to come on.

 

[whitenemesis]

Have you been changing settings in the cluster menu? One can set the headlights to "constant" so they come as soon as the engine is running (like Volvos). I think this happens even if the light switch is in the "Off" position..

 

[Ellsy Tanners]

Have you been changing settings in the cluster menu? One can set the headlights to "constant" so they come as soon as the engine is running (like Volvos). I think this happens even if the light switch is in the "Off" position..

I agree, you see this time and time again, its the first thing to check

 

[golfman]

Thank you for the rapid responses, I should explain a little more, the headlight activation seems to work fine ie switching lights on in dim light conditions and off again when in light conditions. However, sometimes for no apparent reason the lights come on in really bright sunny daylight. When this occours, the lights can't be turned off manually, I've tried turning the engine off, removing the key and restarting but once the lights have turned on they will not go out. Leaving the car overnight resets the problem until it occours again, which is daily after about 10 minutes driving.

I first noticed the problem after a headlight bulb failed, but this is probably just a coincidence.

I hope this has made things a little clearer.

 

[whitenemesis]

If it's happening routinely after the same approx time then I would suggest somthing is heating up and shorting.
When you remove the key do the lights remain on?

 

[bigasotonuk]

Try to eliminate the coincidence, try another headlight bulb, or better still replace both bulbs as a matching pair.
You said yourself it only started after you changed it.

 

[golfman]

Thanks again for the advice, in response to the question, the headlights go off when the engine is turned off and the key removed. I'll check the bulbs again. I actually noticed the problem when a bulb failed, this activated the headlights leaving me with one headlight on that could not be turned off and the issue has continued, now with both lights, as I have replaced the bulb. I'll do a bit of double checking with the bulbs and connections. Thanks again for the advice.

 

[golfman]

headlight sensor

I have now replaced both bulbs with the same make of bulb, checked the connections, even switched on the ignition to check the system can detect bulb failure when they are disconected. However, the problem persists. is there a reset button on these cars like most electronic gadgets have these days?