Ladies and gentlemen,

I am fairly new to cars, however very good with my hands. Is it possible to replace basic rearview mirror with auto dimming mirror with light sensor or would I be looking on the route of replacing entire windscreen? 

Don't do it!  They are not terribly good.  Mine (Octabvia mk3) was OK when I first got the car, though it didn't always dim when I wanted it to... .. and when some **** in a range rover charges up behind you you still got dazzled. 5 years later it doesn't dim very much at all.  I just tested it (blocking the ambient light sesnor and shing a torch at the mirror) and it does dim, but when driving at night it's barely noticeable .

 

However, if you really must ... then the electronics for the dimming function are built into the mirror housing, so it doesn't seem to need any external sensors; but it does need a power supply which I'm guessing your car doesn't have (though as in many cases for optional extras, the wiring harness may be installed but not connected.)

 

To be honest I prefer the old fashioned basic mechanical one on my CitiGo to the fancy electronic one in the Octavia.

 

Sure someone else can confirm the physical elements of making the swap (eg are the mountings the same).

Thanks very much for the reply, I really do appreciate your experience

I have to say that my auto-dim RV mirror is great, I am never actually aware how well it operates unless I switch it off.

17 minutes ago, Warrior193 said:

I have to say that my auto-dim RV mirror is great, I am never actually aware how well it operates unless I switch it off.

I agree, I have the auto-dim mirror in my current Octavia and in my earlier RS4, really missed it in my last Octavia.