blittle

Program your DRL's to be "on" and your headlight control switch will always be in the "auto" mode EVEN if you turn it to off!! ..... try it.....program the option on DRL's to "on" leave your switch in the off position and the headlights will still come on and go off according to the amount of light and if by chance they should come on when you don't want 'em on.... you can't turn them off!! Come on MB.....that's dumb engineering!

redcoupe

Actually, you headlight will be on all the time and then the tail light will come on when it gets dark out

blittle

Not exactly..... I have the "lighting package" with the LED running lights......with that package the headlights are not on all the time - just the DRL's. What you are describing is the standard lighting without the LED daytime running lights. In that case, the headlights act as the "daytime running lights" and are indeed on all the time.

giffie

Yup, mine with lightning pkg does the same thing

SixPak

I agree completely and this is a major pet peeve of mine. Sure having the "Auto" headlight function is fine but at least give us the manual on/off switch as well.

blittle

Yeah.... if MB is going to have such a weird control funtion, they should at least tell you about in the owner's manual! I actually thought something was malfunctioning with the system until I started to check the forum, went out to my vehicle and did a whole bunch to tests ( blocking the sensor with switch on/off and then doing the same with DRL's programed on/off) and found that this IS the way the system works. The truly dumb part of this is that if you really had some serious reason to want to turn the lights off at night and your are in the DRL ON mode......... the only way to turn them off is to shut the car down and THEN reprogram the DRL system to off! By that time the reason for turning the lights off will probably have passed.......

YYZ-E55

Since DRLs are mandatory in Canada, you don't even have the option. Makes drive-in movies an impossibility!

Fourdiesel

What's a drive-in movie?

Brocktoon

DRL cars can set all lights on all the time by flicking the ignition with the light switch in the "on" position. This is how I drive. '80's style in Canada. I go through a lot of bulbs, though...

stmeme

I thought I was going nuts the the other day because of this! Had the trailer hooked up and the running lights were on at 3:30pm ish bright sun with switch set to auto. Thought ok sensor is messed up... I'll just turn the switch to off.... didn't work.... lights stayed on. I was still in the parking lot so I shut the car off. That obviously worked. Turned the car back on with switch set to off.... Lights stayed off... great problem solved... or so I thought. Left the switch set to "off" stared down the road everything was ok for about 10 min then I notice lights were on again. Wow I'm an idot... must must have left the switch on auto.... or so I thought... but nope not switch was set to "off". Got back from my trip, called the dealer and explained the issue. Typical answer... "never heard of such an issue, you must have had the switch on".

Glad to hear I'm not going crazy... But as I have a Canadian version and the drls don't turn off it's going to be fun getting the dealer to fix this. I'm sure the conversations going to go something like this...

Me: when it dark out I can't turn the headlights off can you please fix?
Dealer: if it's dark out why do you want the lights off?
Me: ok... The sensor sometimes thinks it's dark when it's not... So I want to turn the lights off myself.
Dealer: sounds like your sensor not working properly
Me: true, but can you just fix the switch
Dealer: ok we'll look at it for you

Later that day....
Me: did you fix the lights?
Dealer: we ran the diagnostics but the sensor is wrorking just fine... Here's your keys.
Me: &$@-$/@/$&@-:;,$?:/&@/'..... Ok thanks for checking.

aeggroup

Do you know a location of that sensor ? I've got the same problem and would like to play with sensor before I'll go to my dealer.

Thanks.

Brocktoon

On my 2008, the headlamps are the DRLs, so what you suggest would be impossible. On the other hand, as stated above, I generally drive with all marker and tail lamps on during the day. I like the margin of safety it gives pulling out of parking spaces etc. It just give the subliminal signal to other drivers that the car is running. I trust no one or their intelligence after seeing what I have in the past 27 years of driving...

Brocktoon

I think it is in the windscreen behind the mirror.

aeggroup

Thanks.

blittle

That's where it is and I "played with" mine as well..... in the daylight..throw a towel or something over it and the lights come on, take the towel away and they go off just like it's supposed to work. Does it every time without fail. BUT....drive the vehicle in the morning before sunrise, lights come on and STAY ON even as full daylight takes over..... sometimes for a couple of hours and only go off if I shut the vehicle down. All of this with the light switch in either AUTO or OFF. I will be calling my dealer with all of my "research"........ but, there test is simply to cover and cover the sensor and the system WILL work so they will say "sensor works!" I will, however, be interested in their response to the "auto and off being the same!"

MKW

it was a VERY fun date ... when I was in high school !

aeggroup

That is exactly what's happening with my car. Could you please post the result of your dealer conversation/repair if any ?

Thanks.

blittle

calling tomorrow..... will do!

blittle

update...... looks like my next scheduled service is coming up in 2k miles so, i'll bring up the headlight issue at that time. Will post whatever they tell me......

blittle

decided not to wait..... have an appt. for tomorrow am with full documentation on what my headlights have been doing.... we will see what they say!

aeggroup

Thank you for update.

blittle

So here's the story as provided by my Tech guy ( we spent about two hours working with this )......basically two parts: 1. if you have a vehicle with the optional LED running lights, then... when you program the the option to
"leave running lights on all of the time" the "auto/off" function of the rotary switch is overridden and the system is "always on" and the sensors ( rain and light on the windshield ) will be determining whether all of the lights are on or just the lowbeams or nothing at all except the LED DRL's. In other words, if the headlights should come on and you want them OFF... turning the rotary knob to off will have no effect! Both the tech and I agree that this "dumb" engineering but nevertheless is the way it is programed and no upgrades are available as yet. Part 2...... With regard to the headlights coming on when the vehicle is started in the dark and then NOT GOING OFF as the day brightens: the light sensor actually responds to the infrared spectrum.... and, amazingly, a bright or dark blue sky with the sun not directly overhead may be interpreted by the system as "dark" or not "bright enough" and the headlights stay on. The tech actually showed me the Mercedes "in house" service data on the subject: it's entitled "Blue Sky Effect"..... this can be frustrating and/or confusing for the customer. The system is designed to err on the side of lights being on "too long" vs. the potential for the lights "going off" too soon or unexpectedly. The onboard computer looks at the input data and then turns the headlights on or off based on the data..... it is not as simple as the senor seeing light or no light and turning the system on or off. They do have quite a diagnostic test for all of this and all data came back good on my vehicle............... in short, it's going to be this way until there is a better logic sequence in the programing. The good news is ...... there is nothing "wrong" and we will probably never experience the opposite of all of this: having no lights when we need them!

aeggroup

Thank you for sharing this information.

WaveyKat

Question to anyone who has the LED DRL how do I get the DRL to stay on without the headlight being on?
I have a 2011 GL550.

thanks

islandbeef

Complete instructions are in your owner's manual. Under "Daytime Running Lights" or something like that.