Need your help - I'm replacing my '07's Factory Auto Dim/Compass mirror with the GENTX mirror described above. Does anyone know the wiring set-up for the stock mirror....it has 3 wires a white/blue stripe, solid black and solid purple....can anyone tell me what these wires are....one has to be ground, one power and one must be the reverse power line (brightens the mirror when in reverse)?

TIA