I do not believe there is anything that can be done via forscan. All of the sensing and control functions are done by the rearview mirror itself which then controls the side mirror. I disabled mine by disconnecting the connector on the rearview. You can leave the connector in the mirror, but not fully snapped into place, no more dimming and no loose wires to deal with.
Wow good to know. Is there anything else that will not work by unplugging this?
Nope, just kills the dimming. No warnings, DTCs, or other side effects. That is the only purpose for that connector, power in and control out for the side mirror
