Whitenemisis,

Look in your mirror, I know it was a retrofit & its possible it was supplied as a memory part ....

On memory mirrors the mirror clips to the 'memory' sensor , and you can probably see the power connector to the memory sensor if its there.

You remove the mirror by pushing the bottom edge in, then you can see the clip that holds the glass on, which you hook up.
When you reassemble the mirror, you put the clip back into position and there is a little ridge you can force the clip under which is easy then to 'knock the clip off the ridge' with a small screwdriver once the mirror is back flat against the sensor.

Cheers

Richard