Auto Headlight Sensor

[tokage]

I had the windshield changed out on my 2007 MS3 the other day, and since then, I've noticed that when I have the headlights in AUTO mode, they don't turn off during the day the way they used to. I'm thinking there might be something blocking whatever sensor it uses to determine how bright it is outside, but I haven't been able to find it. Does anyone know where the light sensor is that controls the headlights?

Thanks,
toki

[ForestGrump]

The light sensor is on top of the windshield in the middle. The mirror mounts to the windshild where the sensor is. Check there is nothing blocking the sensor. Maybe the sensor is unplugged? hell you're in SJ. give me a call. I'll PM you my number

tokage, I just had my windshield replaced, too, and am having the same problems. The glass co. even replaced the sensor pack, which didnt help. They insist I have the right windshield, one for auto wipers and headlights. Did you ever resolve this?

BTW this is the only other info I can find on this problem.

http://www.torontomazda3.ca/forum/sh...sors-dont-work

[tokage]

As others have mentioned, the light sensor that controls the auto headlights is in the rain sensor, behind the mirror. I thought mine maybe had something blocking the sensor, so I tried removing it and cleaning it off, and also cleaning the windshield glass on the opposite side of the sensor. It didn't help.

I ended up finding a copy of the tech manual online, and in it was written a note about how the sensor unit calibrates itself the first time power is applied. I tried unplugging the connector directly from the sensor, but that didn't seem to do the trick, so I disconnected the battery momentarily and this seemed to at least improve the way it's been working. It's still not perfect, but better than before.

If you try this, just remember to write down all of your radio settings and anything you might have in the nav system (if you have one), as it will go back to its defaults when the battery is disconnected.

One last piece of advice I will give is this: when trying to remove the interior cover on the rain sensor, DO NOT pull it forcefully as it will snap off the cheap plastic hooks that hold the sensor to the windshield. I've had this happen to me twice -- once when someone from the dealer was fucking around inside the cab, and once due to my own dumb luck (caught my backpack on it mistakenly) -- so mine is now reaffixed to the windshield with a bead of high-temperature caulk around the edge of the sensor.

Good find. On that power-on calibration, should the sensor be in light or darkness? Are we calibrating the brightness needed for headlights off or on?

[tokage]

I went back and re-read the manual, and actually, the note was about the sensor calibrating itself for raindrops/dirt on the windshield, not for the ambient light level.

There does seem to be an "Auto Light Illumination Level Setting" that can be adjusted in the ECU, but it looks like you need one of the factory module programmers to change the setting. Not much you can do aside from ask the dealer to do it, I guess.

Sorry for the false alarm.

[siarheicka]

I went to the dealership and had the auto-on threshold adjusted to lower level.
That seemed to do the trick.