My pre-loved 2011 XF Premium has the autodimming mirror. Just took delivery on Tuesday. Yes!

Anyway, the forward side of the rear view mirror has a little window lens thingy on the right . I think it's either an ambient light sensor for the autodimming feature, or it might be related to the homelink (garage door opener). Probably the former. Anyone know for sure?

 

I deleted my incorrect post

 

Really? I thought the rain sensor was pressed up against the windshield under plastic shroud. I'm talking about a little bitty thing on the mirror body itself. Here's a picture.

 

This is the one that I believe to be the rain sensor.

 

Well, there is one for the auto headlight feature and one for the rain sensor. The rain sensor has to be within the sweep zone of the wipers to work. That is in the windshield in front of the mounting spot for the interior rear view mirror.

To check the other sensor for function, switch the headlights onto Auto during daylight and put your finger over that sensor, the headlights should come On as indicated by the green dashboard light.

 

I haven't checked but I think you are correct. The mirror "knows" how much to dim by sensing light from in front and from behind. When there is relatively a lot of light from the front, the mirror doesn't darken as much even if there are headlights from behind you, as it assumes you are in a well-lit city street or in daylight, so that you can still see things. When the front sensor senses "dark," it will assume you are out on a dark highway, where it's more important to darken the mirror so you are not blinded by approaching headlights from behind.

You can check this by having headlights behind you and then covering up the forward sensor on the mirror. If the mirror darkens more, then the above description is correct. If not, then it's used for something else, but my bet is for mirror darkening.

 

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I hven't read all the replies, so sorry if this is old news!

The sensor on the MIRROR side, is the auto dimming. (the cars behind shine their lights, and the mirror "dims", depending on how dark it is outside, as sensed by........

The sensor on the BACK pointing forwards, is the auto headlights function. There is usually a little knob for YOU to decide when the side and headlights turn on or off depending on how dark it is outside.

The rain sensor is flush with the screen, and cannot be seen from inside the car. It measures vibrations and refractive indexes of the light entering it to determine rain from wind or bugs!

HTH

 

So, does anybody know where the garage door transmitter is that I'm supposed to point the opener 3-6 inches away from to program? Still trying to figure that one out. It appears I've been trying to program the auto-headlight sensor!

 

I don't think you need to use the remote. The home link should pick up the necessary code from the garage door opening motor if memory serves. There is usually a learning mode on the garage door motor unit. Since the transmitter in the car is radio wave there should be no directionality effect. The transmitter sends a radio signal to the garage door motor from quite some distance away when programmed.

 

That was random. Wrong thread?

 

Spam, i reckon, Escolar!

 

Wrong forum!

 

My 2012 has the same sensor on the forward side (back) of the mirror. According to the operator manual, the sensor is associated with the intelligent high-beam (auto high-beam) feature in the event that feature is installed on the vehicle. I don't have the auto high-beam feature, but the sensor for it is present and is not used.

 

That's trippy, Jerry. First I've heard of that feature. Is it for other markets?

 

Negative, it's part of an option package for the 2012 SC and base XF; however, it's standard on the XF Portfolio and XFR. Since your 2011 has the same mirror, I gather that the feature must have been available for the 2011 vehicles. It may pose a problem for E-Z Pass users that are required to mount their passes just to the right of the mirror mount. The pass may block the sensor unless it is mounted very close to the top of the windshield.