Auto dimming rear view mirror???
 

I was thinking last night as driving home in dark with a guy behind me with brights on..... that I dont think my auto dimming rear view mirror is working nor ever worked since I bought my 2012 FX4 3 years ago. there is a like 24 pin connector on my rear veiw mirror...how can I check that the auto dim feature is working and why so many wires into the rear view mirror?? ok some power and a sensor on back of mirror but goodness a lot of wires into the mirror.

Thanks for any advice on this situation.

I've had 2 vehicles with auto dimming rear view, and neither of them have dimmed near enough. There is usually (I haven't checked my 2017 yet) a light sensor on the front that you can cover with tape, so the truck thinks it's pitch black, which may help, but it may also dim it in the day time as well.

You may have to play with how much it's covered to get it right amount of dimming.
Ford really should have had a sensitivity setting in Sync 3. But that's prolly a Lincoln feature...

On older auto-dimming RV mirrors, there's an ON/OFF switch, and indicator LED. Is your mirror turned on?

Hmm Switch..I will have to look...there is something back there I was fidling with.....I figure it was the sensor area/housing but I will have to get up thre and look at it or take down the mirror and take a pic to see what it is??

I may have to put a multi-meter on it as im sure once is a constant power + wire to activate it when the sensor tells it to??

make sure its getting power..... I will have to take a pic of it and see/ look for a switch.....

Seems to me putting tape over the sensor would defeat the purpose of the sensor. The mirror is supposed to dim in bright light. Blocking the sensor would keep it from dimming. Or am I missing something? At least that is way it worked on my Jeep before I traded it for my F150.

there is a sensor in front of the mirror for ambient lighting, and one in the glass itself which senses the lights behind you