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View Full Version : Auto headlights stay on all the time



sna77
12-03-2011, 10:13 AM
Anyone else had this issue? My lights seem to be on all the time. I just replaced both bi-xenons with new AL ones. I'm not sure if the problem existed before I replaced the headlights though... It may have been like this for a while and I just noticed it...

Where is the light sensor anyhow?

Mtnman
12-03-2011, 11:33 AM
Its in with the rain sensor. Do you rain sensing wipers work? If the fuse that is responsible for both of these is blown or removed, u have adjustable speed wipers, but ur lights wont work on auto. They will just turn on. I removed this fuse cause my rain sensor is shot, and I wanted intermittent wipers at least.

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Hermes
12-03-2011, 11:35 AM
there should be extra fuses in the fuse box, just try changing the one that controls the sensor

sna77
12-03-2011, 01:37 PM
Havnt had a chance to check the fuse yet, but it appears they are now working. I wonder if there is something blocking the sensor. Where is the actual sensor that detects if it si dark out?

danewilson77
12-03-2011, 01:42 PM
Havnt had a chance to check the fuse yet, but it appears they are now working. I wonder if there is something blocking the sensor. Where is the actual sensor that detects if it si dark out?

It's the lil hole, right below the headlight switch.

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sna77
12-03-2011, 01:46 PM
Ohh... inside the car--so shadows can determine if the lights are on etc. I bet that was the issue

danewilson77
12-03-2011, 01:51 PM
Ohh... inside the car--so shadows can determine if the lights are on etc. I bet that was the issue

Perhaps....

Don't know for sure....but shouldn't headlights go out after a pre-determined time, with the engine not running?

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Hermes
12-03-2011, 03:13 PM
It's the lil hole, right below the headlight switch.

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No, it's the one on the rear view mirror mount. I can make mine turn on if I put my hand over it

danewilson77
12-03-2011, 03:20 PM
No, it's the one on the rear view mirror mount. I can make mine turn on if I put my hand over it

Got it. What's the other hole for?

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Hermes
12-03-2011, 03:34 PM
Not sure. There is also that little sensor on the back of the mirror itself that I'm not sure what it does

kayger12
12-03-2011, 03:34 PM
Got it. What's the other hole for?

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I believe I read something in the past about the dash/climate control/nav lights adjusting to the ambient light inside of the car. Not sure though.

Whitexi
12-03-2011, 04:18 PM
The sensor on the switch is for what Keith said. The sensor on the back of the mirror its self is for the auto dimming feature if I recall.

The rain sensor aka RLS ( rain light sensor ) controls the headlights and the wipers. When it fails it defaults ( supposed to at least ) to the headlights being on always and the wipers should return to an intermittent mode. Removing the fuse results in the same out come.

If the sensor is fuged up say from a bad windshield install the sensors ability to work could be compromised. This could be a problem because then the car may think its working and the sensor may be acting like how its supposed to. If the adhesive that's used to attach the sensor to the glass has to many bubbles or a few in the right spot it will cause issues. The RLS is located behind the rear view mirror and is attached to the windshield. The sensor emits a infrared beam that detects the rain on the glass and then will adjust the wipers according to how often/ much the infrared beams are interrupted. In the same sensor is the part that measures the ambient lighting and then signals to activate the headlights as needed.

The RLS is able to be adjusted to I believe for the auto lights feature using one of the software programs to be less sensitive to the ambient lighting. Adjusting the turn dial on the wiper stalk used to activate the wipers adjusts the sensitivity of the rain sensing wipers. Down less sensitive up more sensitive.

Hope this helps any.

Stu
12-03-2011, 05:02 PM
The light sensor on the actual light module itself automatically controls the LED brightness for the radio and dash. It will dim if it is cloudy and get brighter if it is bright out. It's a nice little feature to keep everything easy-to-read.

The light sensor on the front of the mirror helps to scan how bright it is in front of you and compare how bright it is behind you vs. in front of you to avoid accidental dimming due to headlights of oncoming cars or street lights shining into your car. Very neat.

The rain sensor itself has a built-in light sensor that controls the automatic headlights. It's a bit finnicky at times. Sometimes it will turn on around dusk when it is not dark at all but not turn on promptly when it is really cloudy out and raining (it eventually does). It will also monitor the number of swipes by the windshield wipers and turn on your headlights automatically if it begins to rain.

If your lights are on all the time, it could be due to a bad sensor or dirty windshield. The sensor itself can be replaced very easily: just undo the plastic mirror base, unplug the sensor, and swap in the new one. The reason why a bad sensor is a possibility is because I have seen a thread in which someone put in an automatic LCM into their car that did not have automatic headlights. Leaving it in the auto position left the headlights on all the time.

johnrando
12-03-2011, 08:27 PM
This is good info. I've never noticed my interior lights dimming or getting brighter though. I've used the rheostat adjustment for that.

ELCID86
01-20-2014, 12:53 PM
Automatic headlights on during the day:
I noticed today that my lights were on at 10am on a cloudy but bright day. I read through some of this post and am wondering if it is the RLS (Rain Light Sensor) or the new windshield I had installed a few months back. As you'll recall the rain sensing wipers were not working correctly so I pulled that fuse and am using them as intermittent wipers. Any way to isolate the problem?

sna77, did you resolve your issues?

Mtnman
01-20-2014, 06:26 PM
Shawn,

The auto light sensor is definitely related to the rain sensor fuse. I had my windshield replaced as well, and also had issues with the auto wipers. I did as you did and removed the fuse to use them as intermittent wipers. At this point, i also lost the auto wiper functionality. I was told by the windshield company that the sensor should be rest by bmw. I was told by bmw that there is no way to "reset" the sensor. I sold the zhp before i figured out who was at fault.

ELCID86
01-21-2014, 06:23 AM
Shawn,

The auto light sensor is definitely related to the rain sensor fuse. I had my windshield replaced as well, and also had issues with the auto wipers. I did as you did and removed the fuse to use them as intermittent wipers. At this point, i also lost the auto wiper functionality. I was told by the windshield company that the sensor should be rest by bmw. I was told by bmw that there is no way to "reset" the sensor. I sold the zhp before i figured out who was at fault.

Thanks. I've reached out to the windshield guys. Am also considering buying a used sensor to see if that helps.


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WOLFN8TR
01-21-2014, 07:01 AM
Sub'd.

az3579
01-21-2014, 02:58 PM
Did you get OEM glass, Shawn? If not, that could possibly be the cause of your problem.

Mtnman
01-21-2014, 04:45 PM
I was given the run-a-round when it came to my sensor. I never had a new one put in, but was told mine looked "worn on the contacts" or some crap like that. Hope you resolve it.

ELCID86
01-21-2014, 05:21 PM
Did you get OEM glass, Shawn? If not, that could possibly be the cause of your problem.

It is Pilkington glass which I understand is an OEM brand.


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ELCID86
01-21-2014, 05:22 PM
I was given the run-a-round when it came to my sensor. I never had a new one put in, but was told mine looked "worn on the contacts" or some crap like that. Hope you resolve it.

I found a guy parting a car that has a sensor for $20. I think it's worth a shot. Glass guys haven't gotten back to me :-/


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