Auto headlights stay on all the time

[sna77]

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]

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]

there should be extra fuses in the fuse box, just try changing the one that controls the sensor

[sna77]

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]

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.

HTC Thunderbolt+TT

[sna77]

Ohh... inside the car--so shadows can determine if the lights are on etc. I bet that was the issue

[danewilson77]

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?

HTC Thunderbolt+TT

[Hermes]

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

HTC Thunderbolt+TT

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]

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?

HTC Thunderbolt+TT

[Hermes]

Not sure. There is also that little sensor on the back of the mirror itself that I'm not sure what it does

[kayger12]

Got it. What's the other hole for?

HTC Thunderbolt+TT

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]

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]

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]

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]

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]

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]

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]

Sub'd.

[az3579]

Did you get OEM glass, Shawn? If not, that could possibly be the cause of your problem.

[Mtnman]

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]

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]

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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[anandoc]

Reviving a really old thread, but I found myself in the same situation this morning. The headlight switch was in the "auto" position and despite it being quite bright outside, the headlamps were on. I haven't checked the fuse etc that was mentioned earlier in this thread.

Shawn, did you ever figure this one out? Was it just a bad RLS sensor?

[BMWCurves]

In automatic mode, my headlights are sometimes on when it's really bright out, and other times stay off when it's relatively dark. I figured the system was functioning fine and just chalked it up to top-notch mid-2000s sensors and software.

[anandoc]

In automatic mode, my headlights are sometimes on when it's really bright out, and other times stay off when it's relatively dark. I figured the system was functioning fine and just chalked it up to top-notch mid-2000s sensors and software.

Is there any way (using PA Soft or other tools) to see the values being reported by the RLS sensor? Does it just report 0/1 for Light/Dark?

[san]

In automatic mode, my headlights are sometimes on when it's really bright out, and other times stay off when it's relatively dark. I figured the system was functioning fine and just chalked it up to top-notch mid-2000s sensors and software.

+1

The calibration might not be as aggressive as on the latest models and I also noticed that there is a lot more hysteresis built into it.


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[Sockethead]

Yes it can be re-calibrated though I'm not sure which tools you use for that...

[az3579]

In automatic mode, my headlights are sometimes on when it's really bright out, and other times stay off when it's relatively dark. I figured the system was functioning fine and just chalked it up to top-notch mid-2000s sensors and software.

Mine will sometimes turn the lights on when it's too bright outside, but never had the issue with the dark. They always turn on when it's dark enough to warrant lights. The exception to this is when it's slightly overcast. In this case it could possibly be acceptable to drive without lights, but they "should" be on, so that one is a grey area (see what I did there?).

[ZHPizza]

I'm of no help to you, only to say that I don't keep my lights on Auto so that they're not coming on when I go under a bridge or pull in/out of the garage. It's my understanding that short on/off cycles kill xenon bulbs, so I only flip it over to Auto at night.

Spenser knows more about this shit. Let's see if I can tag that ass @704sw

[az3579]

I'm of no help to you, only to say that I don't keep my lights on Auto so that they're not coming on when I go under a bridge or pull in/out of the garage. It's my understanding that short on/off cycles kill xenon bulbs, so I only flip it over to Auto at night.

Spenser knows more about this shit. Let's see if I can tag that ass @704swThe lights don't turn on/off fast enough to cause damage to the bulbs. If you put it in Auto, you'll notice that it takes a second or two for them to turn on, and when they do, it takes them a few seconds to turn off.

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[704sw]

Spenser knows more about this shit. Let's see if I can tag that ass @704sw

Consider dat’ass tagged. I mean...how can I help?


I'm of no help to you, only to say that I don't keep my lights on Auto so that they're not coming on when I go under a bridge or pull in/out of the garage. It's my understanding that short on/off cycles kill xenon bulbs, so I only flip it over to Auto at night.

Yep, the short cycling is bad for them. It pisses me off how every BMW dealer I’ve ever been to for service puts them on auto, and it’s of course just dim enough inside the bays to trigger the lights. I’m a big fan of Morimoto bulbs, but I’m also smart enough to know they may not be as durable against short cycling as an Osram/etc.. Sure it’s not *that* expensive, but it’s an unnecessary expense nonetheless.

I never drive in auto unless it’s dark. I did the other day so I could post the pic of the annoying green LED, and immediately remembered why I don’t: raining and overcast, mid afternoon but pretty dark, and the lights decided they didn’t need to be on. Not a great idea in the land of texting and driving soccer moms with 3 row urban assault vehicles.


In automatic mode, my headlights are sometimes on when it's really bright out, and other times stay off when it's relatively dark.

This. Luckily I conditioned myself not to use auto because in the X3 you don’t have manual control of the fogs in auto (they activate as corner lights when turning). But it was a catch-22, as the X3 adaptive range-of-motion was about twice that of the E46.

If it’s overcast, or just dim enough for me to want my tails illuminated, I’ll put the parking lamps on, and activate the fogs. I really want an updated LCM so I can turn on DRL tails.


I figured the system was functioning fine and just chalked it up to top-notch mid-2000s sensors and software.

As good of an explanation as any.


In this case it could possibly be acceptable to drive without lights, but they "should" be on, so that one is a grey area (see what I did there?).

Hey-o! If this was Reddit I’d say “take your stupid upvote and get out of here” :biggrin


The lights don't turn on/off fast enough to cause damage to the bulbs. If you put it in Auto, you'll notice that it takes a second or two for them to turn on, and when they do, it takes them a few seconds to turn off.

I’ve heard both arguments. I do know it stresses all components, not just the bulbs. Just like in fluorescent lighting, frequent short cycling can cause damage to the ballasts as well—well, damage might not be the best word, but you’re drawing down from a finite number of ignitions which each component can handle. The ignition is what wears the most on HID components. It’s just something I like to avoid when possible.

[Sockethead]

Hmmm every time I take my car to the dealer, the lights are in the off position when I pick up...

[704sw]

Hmmm every time I take my car to the dealer, the lights are in the off position when I pick up...

I’ve been to three, all different networks. Hendrick, Crowne, and whoever runs the one in Wilmington.

[nextelbuddy]

I wonder how possible it would be to retrofit the adaptive motors from the coupe headlights to the Sedan. we already do complete projector retrofits. would be so awesome to have adaptive headlights in sedan and then be able to code it in the LCM.

[Sockethead]

Try it and let us know how it turns out ;)

[nextelbuddy]

Try it and let us know how it turns out ;)

i need to get a set of broken lights to take them apart and study them. i'm assuming they get a signal from the steering angle sensor as well as the sensors on the control arms that sedans already have unless the control arm sensors are different between coupe and sedan as well.

anyways i wont take this off topic it was just a thought. carry on!

[Dual]

I've been dealing with a lot of confusion concerning lighting configurations lately and I've kind of lost my bearings. With my bi-xenon adaptive setup, which lamps should be lit in DRL mode? I'm getting outer headlamps and amber turnsignals regardless of DRL setting in PASoft.

[704sw]

I've been dealing with a lot of confusion concerning lighting configurations lately and I've kind of lost my bearings. With my bi-xenon adaptive setup, which lamps should be lit in DRL mode? I'm getting outer headlamps and amber turnsignals regardless of DRL setting in PASoft.

If your switch is set to 12:00, you should only have the inner reflector bowl illuminated (the H7 bulbs nearest the grilles).

One to the right should be the H7 inner bulbs, plus the amber indicators.

[ELCID86]

Mine will sometimes turn the lights on when it's too bright outside, but never had the issue with the dark. They always turn on when it's dark enough to warrant lights. The exception to this is when it's slightly overcast. In this case it could possibly be acceptable to drive without lights, but they "should" be on, so that one is a grey area (see what I did there?).

Same here.

[nextelbuddy]

If your switch is set to 12:00, you should only have the inner reflector bowl illuminated (the H7 bulbs nearest the grilles).

One to the right should be the H7 inner bulbs, plus the amber indicators.

yea, i think hes talking about the outer parking lights and wants to do a parking light delete.

DRLs are always in the inner Highbeam light areas. USA uses DIMMED H7 bulbs and Euro uses actual city light sockets inside the same part of the housing.

[anandoc]

Getting back on topic...is there a way for me to figure out (using INPA, NCS Expert or whatever) whether the light sensor part of the RLS sensor is working as it should or not? I have now tested the "auto" setting in clear daylight as well and the lights stay on at all times.

[Dual]

Apologies for going off-topic- I thought I might be experiencing the same problem. Best to all.

[nextelbuddy]

Getting back on topic...is there a way for me to figure out (using INPA, NCS Expert or whatever) whether the light sensor part of the RLS sensor is working as it should or not? I have now tested the "auto" setting in clear daylight as well and the lights stay on at all times.

Yes using INPA there is a diagnostic mode to test the RLS sensor. I used it when I wanted to make sure my sensor was working after I did the retrofit of RLS to my car.

[anandoc]

Yes using INPA there is a diagnostic mode to test the RLS sensor. I used it when I wanted to make sure my sensor was working after I did the retrofit of RLS to my car.

Thanks! I have never used INPA before, but I am quite familiar with NCS Expert. Do you have any step-by-step directions handy by any chance?


Apologies for going off-topic- I thought I might be experiencing the same problem. Best to all.

No issues at all my friend!