Automatic Lights Come On In Bright Sunshine

[Filby]

The automatic lights on my manual IQ2 (2011) work fine when it gets dark but they also have a tendency to come on in bright sunshine - particularly when the sun is at a low angle. Dealer says he hasn't heard of this before. Ha anyone else experienced it? If so, is it curable?

[Red Yaris 54]

The automatic lights on my manual IQ2 (2011) work fine when it gets dark but they also have a tendency to come on in bright sunshine - particularly when the sun is at a low angle. Dealer says he hasn't heard of this before. Ha anyone else experienced it? If so, is it curable?

The characteristics of the automatic light sensors fitted to many modern cars will turn them on when it becomes dark or when the sensor detects a large amount of infra red light as associated with the sun at a low angle

The only way around this is to turn off the automatic function until the sun has risen above the yardarm..........Kinda defeats the object of automatic light sensors :)

[tarquin]

Also make sure the sensor at the front of the dash board and too the right is clean. Dirt on it could cause white light to refract across its surface and produce infra red like a prism triggering it

David

[tarquin]

Also dirt/dust accumulating on it causes it to come on early and flips on and off with minimal light change. Give it a clean anyway

David

[Soeley]

The sensitivity for them can also be adjusted by the dealer, they must do it by plugging it into the computer.

[Dark Matter]

The automatic lights on my manual IQ2 (2011) work fine when it gets dark but they also have a tendency to come on in bright sunshine - particularly when the sun is at a low angle. Dealer says he hasn't heard of this before. Ha anyone else experienced it? If so, is it curable?

This baffled me when I first got my iQ - so much so I nearly turned the auto off. But I think I understand it now. You need to accept that when the sun is low it can be shining brightly in your eyes , but the sensor can be in relative shade thanks to buildings , hedges etc. casting shadows. Some sort of built in delay (no doubt to protect bulb) means that once the lights are on they need a significant "bright" period before the go off again.

[Filby]

I don't think Dark Matter's explanation can be correct. When it is light but cloudy the lights stay off. Then when the sun comes out they come on. There is no way that the sun coming out can reduce the amount of light falling on the sensor. I have had other cars (three Peugeots) which don't have this problem.

I am not sure why infrared light should cause the cause the sensor to think "dark". Digital cameras detect infrared and visible light equally (I always use my smartphone camera to check whether my TV remote is working as it will "see" the infrared beam). It seems perverse to choose a detector which will interpret infrared light in the opposite sense to visible light. I will try the cleaning trick but my windscreen and dash is usually pretty clean.

The IQ goes in for service on Friday so I will ask them to check the sensitivity (thanks for the tip that this is adjustable). They do tend to come on early anyway so a little less sensitivity will be a good thing.

Thanks for all the comments.

[Dark Matter]

Yeah, I may be wrong and I guess you could actually have a fault. My thoughts were based on my experience driving home one evening when the sun was quite bright but low and casting long shadows and so the car was effectively in shadow. I almost have the opposite issue. In some circumstances I don't think the lights are sensitive enough. Example - I have just driven in to town It is chucking it down and really dull. The lights didn't come on automatically - most other cars had their (manually operated?) lights on. I would be cautious in asking the dealer to turn the sensitivity down.

[tonyishuk]

A new feature ?? Auto DRLs ?

Rgds