mine doesnt seem to dim as early as id like - i assume there is no adjustment? (Focus ST3 2018)

 

I dont have privacy glass (long story relating to pre - reg and car mix up....) but it just seems to stay un dimmed even when fairly bright lights behind me.

 

Also, is the sensor dot supposed to be top or bottom of mirror - my older s-max has the sensors at the bottom, albeit in the frame of the mirror.

Is the problem only around dusk or when it's fully dark as well?  Technically there's no adjustment...but you could put a small filter (bit of tint film) over the front light sensor to make it think it's darker outside than it actually is if it's only an issue at dusk.

If it's happening when fully dark, do you have a dashcam fitted in front of the light sensor?

The dot sensor is at the top of the glass in newer Ford mirrors.

Mine is quite sensitive, you don't have anything blocking/lighting up the front sensor? Like a dashcam?

Mine’s also very sensitive on a 15 plate titanium. As soon as someone is behind me it dims very quickly. 

Perhaps yours is faulty?

4 hours ago, TomsFocus said:

do you have a dashcam fitted in front of the light sensor?

That would produce the opposite effect to what Abbadon is complaining about. It would dim too soon. I know because I made the mistake of blocking the sensor with my dashcam and it took a while for it to dawn on me that this had made the mirror unusually dim during the day.

8 minutes ago, mjt said:

That would produce the opposite effect to what Abbadon is complaining about. It would dim too soon. I know because I made the mistake of blocking the sensor with my dashcam and it took a while for it to dawn on me that this had made the mirror unusually dim during the day.

 

If there is a screen or LED on it, it could be illuminating the sensor.

3 minutes ago, alexp999 said:

If there is a screen or LED on it, it could be illuminating the sensor

Fair point.

15 hours ago, mjt said:

That would produce the opposite effect to what Abbadon is complaining about. It would dim too soon. I know because I made the mistake of blocking the sensor with my dashcam and it took a while for it to dawn on me that this had made the mirror unusually dim during the day.

Not if the dashcam screen is permanently lit as Alex suggested...  My screen got stuck on one night, power surge I think as there were other faults at the same time too, anyway the screen illuminated the front sensor so it thought it was daylight, I got blinded all the way home at rush hour on the dual carriageway lol.

on a Mk2.5 I was surprised how dark it needed to be before it started to dim.... 30 mins too late from any other car BM, Merc, Vauxhall, I've had with a proper mirror

no dashcam fitted.

I just feel like id like it to dim slightly earlier than it is. As Botus says, my previous cars, inc the S-max seem to dim that little bit sooner, so that i never felt like it was an issue.

no further ideas?

 

last week stuck 3 layers of scotch tape over the sensor.....

owner now reports it works exactly as it should (in line with how other manufactures make auto dim mirrors)

 

 

oh right, so I assume the sensor is somewhere on the front of the mirror housing? 

There are two sensors on the mirror.  One is a dot on the glass facing rearwards, the second is on the other side facing the windscreen.  When the light coming from behind is greater than the light coming through the windscreen the mirror will dim.  Make sure the sensor looking through the windscreen is clean.  

23 hours ago, Botus said:

last week stuck 3 layers of scotch tape over the sensor.....

owner now reports it works exactly as it should (in line with how other manufactures make auto dim mirrors)

3 layers of the flimsy opaque white stuff, over the sensor on the front left side of the mirror housing