Originally Posted by Jose_JN
Unfortunately you have to buy a new mirror always.
You must have rain/light sensor and auto dim wiring for installing this, but the FLA sensor is inside the mirror and you have to change the whole mirror.
Don't worry it is not so much expensive... You can find it on eBay around 150€
Install the auto dim wiring is so easy:
Check this if you don't have it
Do you have the correct part # for the mirror that's needed to do this retrofit? Isn't there a activation button that needs installed as well or will it just be on if you put the HL switch on auto?