Auto dimming rear view mirror V40 CC
 

Hello to the Forum. I'm a newbie. I bought a used 2018 V40 CC T5 Awd last July.
The Volvo dealer said it had an auto-dimming rear view mirror, but on collection this proved not to be the case. Long story short, they said if I obtained one, and had it fitted they would pay for it. I've had a genuine Volvo part fitted but it only operates for a few seconds the shuts off. I suspect it's a software issue and my local dealer says he cannot integrate it as it was not factory fitted.
Fair enough, but can I simply wire it up bypassing the cars computer? If so, does anyone know the wiring diagram for the mirror, basically so I don't get the polarity wrong?