Rear View Mirror

**bennyk** · 26th September 2007, 09:54

....on the non mirror side of my rear view mirror, i.e the part of the mirror that faces towards the bonnet, there is a hole with some sort of sensor?! in it. Any ideas what it does?

Thanks

**Harry** · 26th September 2007, 09:57

i think it's used for two things. it measures the ambient light outside so that the self dimming mirror can function, and also uses that ambient light reading to switch on the little light bulb at the base of the rear view mirror. i think that's right anyway.

**bennyk** · 26th September 2007, 10:00

Hmmm thanks Harry

**Harry** · 26th September 2007, 10:01

Originally Posted by bennyk

Hmmm...

what's the Hmmm for? are you not convinced?

**Big Sig** · 26th September 2007, 10:10

Is it not for the auto lights too if fitted?

**Harry** · 26th September 2007, 10:16

Originally Posted by Astrase20

Is it not for the auto lights too if fitted?

yep...i think it would be used for that too.

**denzo** · 26th September 2007, 10:36

No, the auto lights function has a sensor on the dash board .... i think

**Big Sig** · 26th September 2007, 10:38

Originally Posted by denzo

No, the auto lights function has a sensor on the dash board .... i think

That little lump on the centre of the dash is for the climate control.... could be another sensor there too though.... anyone know for sure

**john_k_sri** · 26th September 2007, 11:17

Originally Posted by Harry

i think it's used for two things. it measures the ambient light outside so that the self dimming mirror can function, and also uses that ambient light reading to switch on the little light bulb at the base of the rear view mirror. i think that's right anyway.

The little light bulb you refer to is called 'indirect night lighting' which shines on the centre console and gearstick area, when it is dark. You can test this in the daytime by covering the sensor with your fingertip before switching on the ignition, and it should illuminate and remain so until the ignition is switched off. Standard on all pre-facelift except for LS/Life, Expression and Club trims. Not sure about facelifts though.