Daytime Running Lights

Greyrider

Guest
My Altea Xl has the Bi-Xenon Adaptive Headlight system which comes with Daytime Running Lights.

My handbook states that when my lights are set to AUTO and it is daylight, then the Daytime Running Lights will be on.(Unless I have disabled them)...With me so far?

Upon entering a dark tunnel my handbook states that my DRL's will go out and my headlights will come on. Upon leaving the tunnel my headlights will go out and my DRL's will come back on.

However, at night, (the same as a dark tunnel as far as the sensor is concerned) my DRL's are on as well as my headlights. Aren't they meant to go out or do I have to put the switch to manual dipped beam headlights? In which case why have Auto?

Any ideas anyone?
 

neilcw

Guest
I don't really know much about these things as I've never had a car with either. Actually I tell a lie, I used to have a Volvo V40 with DRL's so I rewired the headlight switch so that only the sidelights were on when in the 0 position :D In answer to your question maybe the light sensor behaves differently depending on whether there is a sudden change from light to dark i.e. driving into a tunnel and gradual darkness/starting the car in the dark. It's just a theory but it makes sense.

Personally I would disable both because I don't like either of them. A lot of DRL's nowadays are only on the front and they are quite bright so when it gets dark people don't feel the need to put their headlights on meaning they are driving with no tail lights at all. I also find auto headlights over sensitive on a lot of cars. I've seen some on the motorway where they come on every time they go under a bridge even though it's not dark so the bloody things are on-off all the time. I once had a Honda Accord behind me on a motorway in heavy rain during the daytime and the headlights were flashing on/off constantly because the sensor couldn't decide whether it was light or dark. My manual headlights work perfectly :whistle:
 

Hampton Caught

No It's These Trousers
Dec 8, 2009
35
0
Near Hampton Court
Neil, I know just what you mean.

I haven't had daytime running lights on any of my cars and I wouldn't want them either. As well as the valid observations you make, they use (a little) bit of extra juice and that's going to have an effect on mpg. Given that fuel's now £1.20 a litre or more, which is nudging £5.50 a gallon, I'd rather save the money over a year and not have the extra lights on. Like you, I find the manual lights work fine.

My Freetrack does have auto lights but I've hardly ever used them - in fact, only to experiment and on the odd occasion I've needed the 'get you to your front door' headlight feature.

That said, I didn't think I'd ever use the auto-wipers but find them excellent most of the time. Overtaking lorries on rainy roads is an obvious exception - they can't anticipate as well as me!

Back to Greyrider's query, it does look logical that the sensors can sense the difference between night gently falling and a sudden darkness caused by a tunnel. Mind you, since when has logic had anything to do with it?!

Cheers, Steve
 

freetrack

Guest
I have the same set up, bi-xenon lights with DRLs. There are actually 2 bulbs in the DRLs. One for DRL and the other one as parking light. It works the way you specified, but in the night the parking bulbs are on with bi-xenons and in the day the DRLs' bulbs only.
 

Greyrider

Guest
Thanks for the replies everyone. It's strange that the parking lights are on when the Bi-xenons are on at night. I see plenty of cars with just their Bi-xenon's on at night without the yellow glow of surrounding bulbs in the light cluster. It's just an aesthtetic thing I suppose....

Greyrider.
 

freetrack

Guest
Thanks for the replies everyone. It's strange that the parking lights are on when the Bi-xenons are on at night. I see plenty of cars with just their Bi-xenon's on at night without the yellow glow of surrounding bulbs in the light cluster. It's just an aesthtetic thing I suppose....

Greyrider.

Well, this is the first time I have bi-xenons, but in all other cars I had the normal lights were always on with parking lights, so I think it is the same, and on top there are the DRLs.
 
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